I haven't seen Rush since the Permanent Waves tour(!), but if they are even half as good live now as they were then, they should still be pretty darned worthwhile.
I read an interesting interview with Motorhead's guitarist, talking about what a challenge it is to continue to make albums, decade after decade, on the same premise. How to make it fresh? Townshend has said the same thing about writing Who songs, which not only have to fit the premise of the band, but then require approval by Roger's brain and pipes.
I can certainly appreciate the virtues of quitting while you are ahead. But as a fan who also plays, I find more merit in watching how established greats work their way out of creative cul-de-sacs; it is a much more useful demonstration than perfection. At least for a mere mortal like myself, also trying to find a foot forward.
Old guys need heroes too -- maybe more so.