I suppose it boils down to ( preferably ) getting old gracefully . Jimmy Page has done it nicely ( although he was understandably compared to someone's Grandma on the forum last year ). Also Robert Plant, Roger Waters, Dave Gilmour - and even Tom Waits seemed to have turned their later years into an admirable spectacle.
In fairness, poor Joe Perry did look more 'drained' / unwell - as opposed to the unfathomable presentation of Steve Tyler. He did however, give us Liz Tyler ! :)