> There was at least one year's Tour de France in which all but one participant were later found to have been doping. In other words, you didn't get to that level of that competitive activity, if you didn't cheat, because it wasn't possible to outperform people with such a significant advantage.

This is not true. Even during the 1904 Tour de France where 9 people were disqualifed because of, among other actions, illegal use of cars or trains [1] - 27 riders finished the race.

Tour de France in the modern era has up to 180+ competitors lining up, and there hasn't been a case of 100+ riders being disqualified for doping.

[1] https://en.wikipedia.org/wiki/1904_Tour_de_France#Disqualifi...