Because it’s the life they know. And it’s what they love. Deep Purple was planning on calling it a day in 2020. They were going to release 1 last album (Whooosh, very good album), give it a good tour and hang it up. Then of course the world turned off. And after a few months off they all realized, they had no idea what to do with their lives if they weren’t touring. So now they release another album last year (=1 also very good) and have all pretty much agreed they’ll retire when they’re too decrepit to do anything else. When you’re doing the thing you love most in the world retirement just isn’t that exciting. I mean really what’s Carlos supposed to do after he retires? Travel?!
I saw Justin Hayward (lead singer of the Moody Blues) last night. He’s 78. Playing small halls, with 3-4 band members, mostly acoustic set. Worth the trip to town.