Progressive overload = add weight, reps, or sets to whatever you did last workout.
Do at least one more rep than you did the previous session or you are spinning your wheels.
It's not always vanity.
Most professional level athletes are on steroids and competing at that level without them is almost impossible.
Talent and genes are great, but when you are competing with lots of other talented and genetically blessed dudes for million dollar contracts, the one who has an added edge is gonna win.
Plus the whole transhumanism, breaking boundaries in human performance, etc...
Let the people supplement as much as they want.
They're already doing it anyway.