That's like saying no a single bodybuilder ate like a pig before the "insuling GH gut era" ,,,, lol
In reality there were tons of guys that ate like pigs during the 80's in off season yet on stage not a single gut ...
If they did eat as much back then they would have weighed the same but they did not. They would've had a higher bf percentage, on account of the lack of GH and perhaps other nutrient partitioning drugs, but they would've weighed approximately the same. The pros didn't used to weigh 315 when off like Palumbo or 330+ or whatever Ronnie weighed at his largest.
They didn't eat 12 ounces of meat 6 times a day for years on end.
The drugs definitely contribute though. Visceral fat accumulation, some organ growth, just general water retention, which can further swell the stomach, leading to higher chance of diastasis, herniated stomach walls.
A couple of decades back Chad made a smart observation. He said the pros with the worst guts are those with short waists. Makes sense, there is less space.