PED’s have been and will continue to be a problem in sports. The “records” that have been set by those who have used PED’s undetected, inspire those on the way up.
How does a truly average kid (in stature) grow into a behemoth. You can spend all the time in the weight room you want, but you’re only going to get as big as your DNA is going to support. Is that big enough to get him where his dreams want to take him? In most cases the answer to that is a resounding NO !.
Enter the PED, and zoom, all the work in the weight room pays off, he’s got muscles beyond what his DNA would have assigned for his frame, and he’s headed for a career as an athelete. No PED and he’s just another wannabe player who may have played in college, and done OK, but not a star, and definitely not a “prospect” as a professional. That’s a bitter pill for some folks.
You get “house’d” by some guy who’s a “star” but you know deep down that he’s not better than you, but just plain bigger, and you think.... Hmmm, I can’t beat him because he’s just bigger, and if I were bigger I could really take it to him.
The kid whose DNA destined him to be 5'-9" and 130 lbs does not take PEDs and become a 6'-8" 340 lb offensive lineman.
The trend of increasingly larger people has been going on for a century of more. Soldiers in WW-II were on average taller and heavier than their fathers who fought in WW-I. The trend has continued.
If you want to know why players are so big now, ask why kids in general are so big now. The answer IMO is primarily that adults in the 1970s while taller and heavier than their WW-II era fathers, did not grow up in an era of mandated RDAs for vitamins and nutrients in everything they ate.
The 1980s saw the first generations of 18 year olds entirely raised on mandated RDAs and what do you know but that generation was larger than the one before it. 6'-5" 300 lb high school tuba players used to be rare but are now relatively common. Does that mean high school marching band members are using PEDs? No.