Because you can't do it? LOL
a little 16 years old bastard at my gym can bench 370/380 easily, chin up with a plate of 20 kg for set of 15, etc etc, with apparently no effort, and no technic, no knowledge on diet, only drinking beer at college with friends.
but he wasn't interested in power/bodybuilding so he give up.
he was the most gifted guy i ever seen.