Nothing.
Nothing would have also stopped them from becoming some of the most beloved athletes in this countries history, either....PEDS or not.
I also find it interesting that there's an incredible double standard between the NFL and the MLB when it comes to this stuff. We want our NFL players bigger, stronger, faster...capable of incredible speed and incredible power. I've been on the sidelines for those games and I've been in the locker rooms and I can't believe those guys are 100% all real. Sure, they're incredible athletes to begin with but I don't think anyone gets that big and that fast naturally. A football player gets popped for 4 games because of PEDs and no one bats an eye. That's SUPPOSED to happen. And when it does happen, no one really cares because....RAWRRRR FOOTBALL GLADIATOR GRIDIRON WARRIORSRAWWWWRR
But baseball? Threaten a vaunted record if you're a muscular guy and it's the biggest crime ever. They'll keep you out of the Hall of Fame because the very people that are rooting for their 6'5 260 8% body fat linebackers that can run a 4.6 on Sunday are the ones who are crying foul when a baseball player uses a chemical they can't pronounce to make themselves stronger.
It's a double standard, IMO. We care when one athlete does it, we turn a blind eye when another one does it, too.
The issue isn't PEDs, it's making ourselves feel better by damning players who are tarnishing something that we thought was pure when we were growing up.