Race wheels are generally ultra light. Anything with material cut off of it will be generally less durable. That coupled with cutting edge materials & technology make them quite a bit more expensive. Modern wheelsets are where technology a made the best improvement on bicycles. Ride a set of Boras compared to a set of equally high end wheels from the 80's & you quickly notice the easy of acceleration, the smoothness in ride quality & the effort difference to keep them rolling on a long flat. I pick boras as an example only. But, back to the point. Race wheels expensive & fast. Training wheels durable, heavy & still only as fast as you.