I think as well that...
a lot of sports are "cleaner" than 20-40 years ago. BUT most of the sports that are? Primarily "skill" sport. Football, handball, cricket, ice hockey, basketball, baseball for example... I would wager less guys are on something than were back then.
Because the extra attention on drug testing, the societal backlash, the health worries etc? Not worth it as much in sports that - well - dont really require you to be the strongest or having the most stamina to win, and also have a lot of moving parts with so many players on each team etc.
Now, I am also not naïve enough to think that any sport is close to fully clean either... and team sports where pure strength is a bigger advantage? (NFL, water polo, rugby) Yeh, for sure there are higher rates of doping as well still, and in some of these that starts at a younger age too...
but in a sport like cycling (like longer distance running, longer distance swimming and strength based track and field etc)... the advantaged that doping gives relative to chance of winning is significantly more. The risk vs reward is just flipped on its head vs a lot of sports.
90% of winning in a Grand Tour for example, or a marathon, or 1500m swimming? It is having a better V02 Max, having better lactate threshold, having better hemocrit levels.