Could be because the use of performance enhancement drugs are frowned upon these days. Or because being big doesn't make you a great wrestler.
Does anyone remember that Batista was complete shit at the beginning of his career... well for most of his time in the WWE? Not to mention he was injury prone because he was just a big muscular wrestler, with no actual athletic talent.
Batista isn't naturally big, he's a steroid freak.
Rock isn't naturally that big, yes he played football, yes he was bigger, but he's twice as big now as he was when he came back in April, which is 4times larger than he was when he left.
Cena isn't naturally that big, but he packs it on well and maintains it.
Triple H isn't naturally that big, he's probably the smallest he's been since 2000, but he's still over 250 pounds
Austin wasn't naturally that big, but he was still massive in his prime.
A lot of the guys now are athlete, with backgrounds in real sports.
Batista was a weight lifter when Triple h discovered him at a weight lifting show. Weight Lifters are usually big guys, who power lift to get enormous. Swagger and Zigger both come from a background in amateur wrestling, Ziggler is shredded to all shit, if he was to bulk up to the size of say John Cena he would lose his speed.
Punk, Ziggler, Rhodes, the Miz, R-Truth, Ryder, are not small guys they all average over 6 feet in height, and 200 pounds. They might not be 6'4 300pound juice monsters like Batista was in his prime, but their still intimidatingly large guys. I doubt Batista would talk that shit to any of their faces, especially CM Punk.
Batista needs to sit at home and recover from his back surgery and keep his fucking jaws just before he ruins any chance he has in the future of returning to the WWE.
I bet Goldberg didn't think Chris Jericho would choke him out in a fight, but it happened.