It's hard to see that type of game - very much a fad, and also a gimmick - ever come back around again. And I say that as a huge fan, who still has all my toy instruments and plays Rock Band regularly.
But fads just don't repeat. Some settle into long-term niche popularity, like, say, Rubik's cubes or Beanie Babies, both of which are still around but will never again be massive phenomenons. Add in the gimmick, and stuff like Dance Dance Revolution and Guitar Hero, or even Wii Sports, are just never going to happen again. If they want a hit music game, they'll need to come up with a new gimmick, a new twist, not rehash their old one.
That said, I have no doubt that we'll see another music-based fad game again. It just won't be a revival of an old one. It won't be Singstar, Just Dance, Guitar Hero or Rock Band, or Dance Dance Revolution. It'll be something new, even if that new thing is very similar with just a different name.
Like, I could see a singing or dancing game mashup with "battle royale", where people perform briefly, get judged by the crowd, and move up through a bracket.
