There are several classes of natural talent:
1. Very little talent (bottom 20%). At best doping will allow them to remain on the team. Strong incentive only if this is important to them.
2. Mediocre talent (middle 60%). Doping can improve their status on the team, but it still won't be good enough for a pro contract, so little incentive to dope.
3. Decent/high talent (top 20%). Undoped they have a very small chance for a pro contract, but doping increases the chance greatly. Huge incentive to dope.
4. Ubertalent (top 0.1%). A very good chance for a pro contract, even without doping. The risks of doping may not outweigh the benefits at this point. Decent incentive to dope.
It seems to me that category 3 has the most reason to dope.
Dr. Maserati said:
I did, doh- but even including all of them it is still just 16% (or 84% would not dope)- I would not have been surprised if that number was in the 40's. YMMV.
I think it's important to realize that the higher you go, the more clean athletes are filtered out. Many junior athletes do not make it to the pro's, but dopers have a much bigger chance than average.