Also have to note some big guys might be recovering from injury, shoulder injury, knee injury, there just looking to maintain what they have.
I messed up my shoulders, a while ago, I was 230 pound young guy full of lean muscle, used to bench 315 6- 8 times and due to the injury i was benching 135 only for like 15 reps and even that would cause my shoulders burn. Definitly hurts the ego too when you see 160 pound kid lifting more than you, lololol.