You don't know jack about pro endurance sports and esp. road cycling... obviously.
Probably all of the the front half of the field dopes... But it doesn't matter much as they prolly do the same drugs. Better ability, more and better training, timing your form, pushing yourself to the limit on the right day, having a good team, not making tactical mistakes... that sort of stuff is what decides races. I guess it sucks for the guys who are not willing to take drugs.