also remember, car engines run in excess of 30,000rpm, whereas an aircraft engine is typically designed to run at half that. When you double the rpm, you double the wear between the piston and sleeve, and you also increase the abuse to the connecting ron and the bushing that goes on the crank. One way or the other, 2-strokes wear themselves out, thats how they are designed, they don't have the benefit of rings like a 4-stroke. Thats also a good thing though, because the parts count stays down, and they are just simpler all the way around.