Why don't more big men these days MAN UP and play like Shaq used to?

Because Shaq was HUGE! No one comes close to his mass (325+ lb) in today's game. 25-50 lbs makes a huge difference. Shaq's athleticism allowed him to use his size in order to dominate.

Its like saying, why would any heavyweight boxer no a days fight like ali...They dont have the talent to do it...To be a great player like shaq, the most dominant big man ever is not something that anybody can be achieved by just mere hard work and dedication...It takes talent, pure talent combine with hard work and dedication the result is special...Shaq oneal...

To make it clear, im going to give you an example.....

Dwight howard, is the closest big man which many analyst compares him the next shaq oneal...

But no matter what he do, he cant be shaq oneal why? He cant even grip the ball properly, his hands are small, and he doesnt know how to position himself in the post...Because he doesnt have the upper body strength like shaq has and lateral movements...So he cannot be like shaq, no matter what he does...Dwight works hard, go to gym everyday, practice everyday,even asked hakeem olajuwon to teach him some post moves...But still he cant do it,he doesnt have the talent to do it...

Shaq had a back to basket game. Some of the guys today (Dwight especially) dont. Also he ran the middle of the floor, so if he got pushed out of the lane he ended up on the block, where he dominated due to his back to basket game, ridiculous size and strength. Also, young Shaq especially was really athletic, especially for his size

Well if everyone is trying to be as dominant than Shaquille then everyone would cancel out each other and then it would just look like their soft. The real question is can they play like Wilt Chamberlain and the answer is Hahaahhahahaahhahahaha NO

Most big men are simply tall -- not all are built, though. Trust me, in the NBA, it's easier said than done. Shaq was unique in the sense that he was both tall and built, and really talented.