Top judoka, boxers, etc don't compete in MMA, nor would they win if they did, because everyone has to train specifically for MMA to succeed in it. That doesn't mean their skillset doesn't apply to MMA, or that there is nothing to learn from them.
Maybe not top, however, judoka, boxers, etc, do switch to compete in MMA and we see how those skill sets carry over. Thus validating that their skills are useful for one on one competition. Not that this is the argument, but it seems like a good place to point this out. If a judoka says Judo will help improve MMA fighters, we actually have evidence of this, because there are judoka competing in the UFC and Pride. However as far as I know there are no internal specialists competing at the top level of MMA, so to say internal skills will hep MMA fighters is speculation until proven.
Anyways, I"m bored with the topic. I got the answers I was looking for and have nothing else to add.