Well, what happens to some bands who get really popular is that if it isn't lasting, and is more "flavor of the month" as someone put it, they could possibly get dropped from the label.
Once you sort of "hit it big" it is sometimes hard to go back, which has caused some bands to break up.
The only thing so far that annoys me about the Dragonforce popularity is that they are touring with shitty bands.
In Europe, they tour with bands like Power Quest. Here, since they are pushed by Roadrunner, we would have to go to Ozzfest to see them. Even their last tour had crap openers (Not that the openers should matter, but it would be nice to see some more deserving power metal bands support them who could benefit from the exposure).