First, I don't think this is a troll question at all. It's a very valid observation.In part because he's more established than Lang, and also because his name carries a lot of cache on projects. But it's also because he's happy to play 2&4 when asked. Anyone who thinks Vinnie is out there doing Burning For Buddy every day should examine his credits more closely.
Same with Steve Gadd. He's one of the masters, but has a significant amount of work in the mainstream playing fairly straight ahead stuff.
I don't know if Lang, Donati, Mayer et al simply don't want to play straighter stuff, or if their reputation prevents them from getting such calls, but they're not known for playing in bands or with artists. There's nothing wrong with focusing on clinics or in Bozzio's case, doing solo performances. It's just that they're rarely if ever seen in a band situation. I think that most of us believe that a drummer best expresses himself in a melodic, musical context. Solos are fun, but they don't have the staying power of music.
I wonder if our Bermuda has hit on a huge aspect of the issue. Maybe a lot of these clinic, "drummy" drummers really would love to play on a straight-ahead recording but they have a reputation as being "that overly busy drummer with the huge kit" that most producers would never even consider calling them for a gig.
On the other hand, Vinnie has already established he is more than happy to play the 2 & 4 on a gig...or the 9/8, or the 15/16...