I saw the Cramps last week and Lux and Ivy must each be pushing 50 (the band has been playing since 1976 as have the Fleshtones, who released a new album a week later than the Cramps). The Dictators debuted on Epic in 1974 and their new album equalled or surpassed their others. Iggy Pop must be over 50 now.
I've seen James Brown and Little Richard, they may be nipping and tucking the wrinkles.
Link Wray has his wrinkles but at 74 (and one lung) he can still play guitar that has 30 year olds saying "Man, that's too loud!".
I don't see the next generation of performers contributed the same caliber of work. Luckily we can enjoy the older recordings and videoed/filmed performances.