I know someone in a band in pretty much the same situation. Next big thing early 00s band - big label, a few top 40 singles early on & debut album that sold well. They’re still going, but mainly because they enjoy seeing & playing with each other now - as I understand it, it’s in not viable as a sole means of income. When they release a new record, pretty much all of the sales are in week 1.
The guy I know set up his own business. Only one of them is still a full time musician and that’s through playing in a few different bands. I’d imagine he’s scratching a living rather than coining it.