Mr. T (MrT4) said:

35-40 ton 8x8 to carry 6-8 dismounts at near 10mio Eur a piece

A Boxer doesn't cost 10 mio €. The common versions are all around 5 mio € and the armed IFV versions in the 6-7 mio € range.

Mr. T (MrT4) said:

Like Patria 6x6, Pandur 6x6 etc 10 dismounts plus a crew of two, driver and commander,

Neither of these is nearly as capable as the heavy 8x8. The protection of the Patria 6x6 is a joke by modern western standards. Its also not small. Its about as large as a Boxer. Its just lighter. Which is a direct result of its poor protection. If the protection is increased its weight goes up conciderably compromising its off road mobility and it definetly won't swim anymore.
The Patria AMV which is comparable to the Eitan and Boxer in capablility is, supprise, supprise, as large and heavy.

The older lighter and smaller 8x8 and the current 6x6 simply do not fill the same role as the heavy 8x8. The latter ones are capable of operating on the frontline and at an high threat environment typical for COIN and LIC.
The first two are intended for support roles. Not to be shot at or really fight. It attacked they where supposed to smoke and run. With their light armament giving limited self defense capablity. This concept has not worked in the COIN and LIC deployments typical for the first two decades of the century. The heavy 8x8 bunkers on wheels are the result. Not protected and cross country mobile support vehicles are needed again. Hence a renewed intrest in ligher 8x8 and 6x6. But these are not supposed to replace the heavy 8x8 but supplement them.

If you are intrested I recently got some insight in the German procurement program for a 6x6 Fuchs replacement. Why the CAVS program has been joined and most important why there are such drastical differences in price of the different 6x6 vehicles offered.

Definitely interested, as it looks like 6x6 are being resurrected .

As for the Germans joining the CAVS program: this is a move from the MoD. It caught anybody involved in the Fuchs replacement program, one of the slow burners running for years, by supprise. It seems the MoD wants additional contenders for the Fuchs replacement than just Rheinmetall with the high roof Fuchs 1A9. Which actually is a typical German procurement program with the 1A9 directly tailored to the requirements. Since lately Latvia has purchased some Patria 6x6 for ~1 Million € a piece and the price Rh calls for the 1A9 is more than twice that someone in the German MoD decided it might be a good idea and bring Patria into the race. Which at first glance seems like a smart idea.

Now here is the but. A really huge but. As mentioned the 1A9 is tailored to exactly fit the existing requirement for the Fuch replacement. The Patria is not. It turns out after even a brief reading trough the specs that the Patria doesn't even come close to fullfilling the German requirements. Lativia purchased a really basic version. That even lacks essential equipment like NBC-protection, a fire supression system etc. Furthermore the protection is really basic too. STANAG K2 and B2. Since the Fuchs replacement is supposed to operate together with the Boxer fleet a comparable protection level is needed. The Latvian Patria doesn't even have decoupled seating. The engine the Latvians use is a truck engine. Not mil spec. An off the shelf truck engine. Its power to weight ratio (with STANAG 2) is below the German requirement. It also lacks features like day and night vision systems. Of course Patria confirms that the CAVS can be modified to meet the German standards and requirements... but it will definitly not cost 1 Mio. € per vehicle after that anymore.
The Fuchs replacement program really is going to get intresting. The recon and engineer corps, heavy users of the Fuchs, allready added the requirement for the replacement to be amphibious. The Fuchs is the last amphibious vehicles they have. If this capability is going to be retained without purchasing special vehicles the new Fuchs besides having conciderable protection requirements also needs to be able to swim.
 

It really comes down to the details and capabilities. If you want a truck to carry stuff and people around with some armor you can get this rather cheap. Allthough I would argue a Griffon 6x6 or Eagle V 6x6 are a better choice for this than a basic CAVS. If you want/need the capabilities of a real AFV as APC you have to pay for it.

This for example is why the Boxer is so expensive. Its a true AFV. Its better protected than most APC and lots of IFV regardless if tracked or wheeled. At the same time it has really good mobility. Behond what an armored truck can achieve. This of course costs money.

https://euro-sd.com/2020/02/articles/15949/the-return-of-the-6x6-afv/#:~:text=The%20Return%20of%20the%206%C3%976%20AFV%207.%20February,a%20number%20of%20new%20designs%20already%20in%20production.

As seen in the article above, the tyranny of the land and poor infrastructure of less than developed countries has kept the 6x6 alive in theaters usually with less focused internet exposure than the fancy 8x8 contracts. The Guarani is one of those programs whereas the best substitute for a 6x6 (Urutu/Cascavel) is another 6x6. Although the ENGESA golden years will be well missed, the occasional small export batch (Phil, Libano, etc) keeps the concept viable internally and externally.

I don't think the 6x6 ever went away.
The German Army for example operated more than twice the number of Fuchs 6x6 APCs compared to the Boxer 8x8.

In Afghanistan both where deployed together. With the Fuchs being deployed first and serving trough the entire mission. The Boxer joining once it became available.
The main advantage of the 8x8 is the ability to carry more protection. Which means its better for expeditionary use, COIN and LIC. If this is not needed 6x6 work fine and usually fullfill the requirements. With shifting focus the requirements for vehicles also shift.

To me it seems more like the 8x8 taking over the role of sub 30 t tracked APCs and support vehicles.

Do they not fear you end up with 6x6 boxer if you want to integrate too much Boxer like capability into it. I hardly imagine any vehicle with glass windows trying to match Boxer in protection.

If you want a cheap armored amphibian Protolab PMPV is surprisingly cheap at sub-800k Eur  , Protected Multi-Purpose Transport  14 t (empty or equipped - not specified), with up to 10 t of cargo all COTS drivetrain and up to stanag level 4 protection which is more than enough for armored truck

Patria 6x6 resurrection of PASI gen 2 is kinda surprising as PMPV was originally developed as  XA180 replacement and initially, they touted 600k Eur price tag

While Patria was still playing with a 6X6 AMV variant before they sold the whole AMV licene to Poles

Why should they fear ending up with a 6x6 Boxef if this is what they want? The requirements are what they are for a reason.

Besides the Fuchs 1A9 currently fitts the requirements and is not really a 6x6 Boxer. Allthough it Codes pretty clone to that.

The thing is with the recend observations and data from UA the protection requirement is being reworked. As a result the required protection most likely will go up. STANAG Lvl 3 ist currently seen as the minimum. Its likely that there will be  shift to lvl 4. At least for front an roof protection. To adress the submunition and grenades dropped by drones and loitering munitions issue. Lvl 4 will also not be penetrated by most kamikaze drones except for the larger mit spec types.

Window protection is easy. Foldable armored covers. The Fuchs has these. It it id possible to realize these for lvl 4 armor in a sensible way will be seen in the future.

The PMPV is exactly a case of you get what you pay for. Its an armored truck. With the bare minimum of military equipment. Its capabilities even compared to a minimum equiped CAVS are limited. For simple transportation and support tasks such a vehicle is usefull and sufficient. As APC or in any function that will bring it closf to the frontline or in likely contact with the enemy its unsuitable. Its Lvl 2 protection is concidered not suitable at all by the German Army for anything but pure logistical tasks. Depending on how good the mine/blast protection actually is of course. 

Add on armor for level 4 is more or less standard in most 8x8 these days not an issue to add to Patria or any other 

PMVP/Misu ( can be up-armored to level 4 and mine protection  considering its touted as an MRAP likely exceeds Fuchs or Patria AMV in terms of mine protection 

Mr. T (MrT4) said:

Add on armor for level 4 is more or less standard in most 8x8 these days not an issue to add to Patria or any other

Yes of course. If a vehicle has load carrying capacity it can use this to carry armor. But this will directly eat into the usable carrying capactiry. Concidering the PMPV is 14 t empty with Lvl 2 protection for 10 t of cargo carrying capacity uparmoring such a huge vehicle to lvl 4 will propaply eat half the cargo allowance. Which would defeat its purpose. Its a protected truck to carry stuff around.

Mr. T (MrT4) said:

PMVP/Misu ( can be up-armored to level 4 and mine protection considering its touted as an MRAP likely exceeds Fuchs or Patria AMV in terms of mine protection

How well its mine protected also is unknown. There is no reliable info available. I really doubt it has comparable protection to the current itteration of the Fuchs. Which is extremly well protected against direct attacks and blast by 6x6 standards.
The PMPV simply is an MRAP. Its not in the same class as the 6x6 APCs. The manufacturers home page even says so. They also say it uses mostly civillian of the shelf parts. Its in the same class as the Eagle V 6x6 used by the German Army only less mil spec and thus cheaper but at the cost of reduced capability.