Dunno about "dying out"... it's just that it's such an unique mix that truly dominant big men are kinda rare. I mean, that kind of size, with that kind of power... mixed with enough agility to utilize it. Rare 'tis.
Usually, there'll only be one or two in any generation playing. I'd suggest that Dwight Howard's of that ilk, and Andrew Bynum might be too.
http://with-malice.com/ - The half-crazed ramblings of a Lakers fanatic in Japan