Harmonix has made similar claims before, so you can probably expect Rock Band to make a triumphant return at some point.
During a PAX East keynoate address, studio CEO Alex Rigopulos told the assembled media that his team had "grand plans" to bring both the Rock Band and Dance Central franchises to next-gen consoles.
At the same time, he wouldn't officially confirm a new title for either series, although he made it plain that both IPs are "near and dear" to Harmonix. Therefore, they want to tackle next-gen consoles "at some point," even if the interactive music boom has died down. The last entry in the Rock Band series was the old-school digital game Rock Band Blitz ; we haven't seen a full installment (complete with those plastic instruments) since Rock Band 3 back in 2010.
I wonder how Harmonix will bring these titles back…they'd have to update them somehow for next-gen consumption, wouldn't you think?