have you seen the physiques and workloads that nba/nhl/mlb players are dealing with these days? these athletes have more incentive than cyclists to dope ($$$), and the testing in those sports is a joke.
there are obvious performance benefits for traditional endurance sports, but the testing infrastructure is pretty robust and the financial incentives are much less than those big team sports. it's harder to dope (and get away with it) and the financial pressure is less.
I totally believe that a lot of basketball/football/baseball players take something. But the effect won’t be as important as in cycling or marathon or 100 m sprint where you need pure physicality.
The effect doesn't really matter. If it gives you a 2% edge, and you don't take it, then you're 2% off the top. That may be the difference between having a career at all and thinking about what could have been at your desk job.
Sure, there's no drugs that will turn you into prime Messi. But there are drugs that will let Messi play like prime Messi for 90 minutes, 3 times a week, 48 weeks a year, which is incredibly valuable.