Are you sure its not a sport tire, sport touring tire normally offers alittle better life(thats their purpose) over pure sport, atleast I'd want to know specifically what tire it is.
The pure sport tires, normally wear faster in comparison cause of the softer compounds involved.
In addition, the speed of the rider, the road composite, how much of the ride is acel and decel. Or in other words hard accel and hard decel is going to be harder on tire wear. Tight narrow agressive roads are harder on tires than more spread out roads.
Example on street track tire, the Mich Ppower a pure sport tire, I've never bothered with the (rears), cause they are a sub 4000 mile tire for me, yet I know some have gotten 8 or 9,000 mile out of them or as little as 1500 mile. The fronts though offer me enough life and performance under all conditions I deal with on the street for me to not bother with anything else, and its life is comparable to a sport tour front, cant ask for much more in safety /performance and life.
A sport tour (rear) will normally offer 30% to 50% more life over a staight sporttire. Where you have to weigh in is the saftey factor. 100 horse plus bikes are very dangerous without good traction, especially when riding agressively.
0nly 2000 mile on a sporttour tire is an oddity , not something most are going to see on the street. But 3500 to 9 or 10,000 mile like in your case , depending on all the factors is a normal range that can be seen.