Why do the old bodybuilders look so bad now?

If this is a serious question you must truly be retarded OP

Reduced insulin sensitivity after steroid use causing more visceral fat.
Reduced collagen synthesis during use.

I also think they stop following a strict diet,
Maybe the body can't grow/maintain very well natty after being desensitized to high amounts of roids,
could be something with androgen receptors but that's a guess.

Holy shit his tricep is non-existent and his bicep just makes it look worse

Other than that he looks amazing for a 70 year old desu