diuretics wrecked everyone back then - they screw you up fast. i remember reading momo lived for a week without water before the dutch pro which he won. He only drank applesauce for an entire week. Dude was shredded WAY MORE than guys get today.
Today's crop of athletes will have issues with joints, bones growing all funny... expanded organs and distended belly... BUT they do not attain that kind of suicidal conditioning that we used to see.
So I think today's guys will look very weird, but they'll quietly make it to their 60s, at least, thanks to better meds, better monitoring.