They legalized drugs. Even in 3rd division footballers use substances and drugs. Nobody wants to be honest with that, but if you know someone who is a hard-working professional athlete who's living the sport, sleeping and waking up every day for it, he cannot make it without using substances.
Specific and strict food regime is an important factor and it cannot go without that, but also it cannot go without all sort of supplements and even more than just them. How could these professional football players run over 10 km, making around so many sprints on the pitch? Sure, they use it and none of them will admit.
Not to mention American professional sports
, that is a completely another world for the last 25-30 years(and I guess even more).
Those who don't have money to buy all sort of devices, build new infrastructure, install those special pools for exchanging body temperatures, bring quality fitness and physio stuff to work with all these things, buy those supplements
... They'll be like a third world country or one century behind.