Thinking about the age thing, Springsteen has a few years on the Rush boys, and he keeps regularly touring, recording, and giving it some by all accounts.
Could be a few more Rush years yet - they show no sign of stopping!
Maybe I'm wrong here, but hasn't Alex spoken out before prompting speculation, only for it to be groundless? Only remember something being mentioned on a forum about an R40 tour? Seems to be ring a bell.
I do hope they go on, sure we'll get another couple of albums even at their current rate. Not sure if I'd like too much 70s stuff though - records I love (I didn't hear then until the mid-80s), but it was all quite a long time ago....