The top 0.1% of rock groups maybe. The vast majority don't make significant money and probably do it mostly for the love of it and maybe a bit in the hope they'll make it one day.
Art is not a hobby, it's not a labor of love, it's a profession just like web development or project management.
Take a look at the progressive rock band Rush, they've been going since the late 60s. They still love what they do, and have evolved their styles over time.
Even Iron Maiden who I would argue had commercial success and fame have survived a tumultuous time during the 90s and have come back even stronger.
We'll see how long it lasts. He'll probably dedicate himself to writing for a few years and get himself back in shape with long-distance bicycling. But, he'll probably be back. I could easily see him not want to do arena tours anymore though, maybe some jazz gigs or small-venue acoustic sets with Rush.
It's kind of interesting that two iconic drummers from the same generation - Bill Bruford and Neil Peart - decided to get out of the industry.