I mean, you’ll find people using PEDs in any sport, despite the risk of bans and everything. Steroid use is also rampant among bodybuilders.
There is an “obvious market”, but why do such sport leagues or federations that openly allow those drugs exist?
I can imagine that such a thing existing would create an immediate and widespread health problem with lots of people, athletes or not, using those performance enhancers and accidentally fucking themselves. But what else could be a problem?
Just because it hasn’t been said yet, this already exists in bodybuilding. The professional league, the IFBB, which hosts the Mr. Olympia competition, does not prohibit drugs and they are de facto required. Essentially every IFBB bodybuilder uses steroids, and it’s a very open secret.
Something that does need to be considered here is that not all sports necessarily benefit from steroids, at least not nearly as much as bodybuilding. More muscle isn’t necessarily always a good thing if it makes you heavier or less mobile, so there’s already some limited regulatory effect from that as well.