As I've remarked elsewhere, there's probably no way anyone embarking on a musical career forty years ago was looking at it as a long term career, but, equally obviously, after you've been doing something for a while you start to find that there aren't many alternative career paths. It’s not as if great technical mastery of a musical instrument flows over into other career paths if you rule out playing or a salesman’s gig in a music shop.
I started off teaching as a temporary fill-in measure while I finished off my degree and thought I'd end up in academia. Didn't work out that way, and I was still in the classroom thirty years later. It wasn't a conscious decision, I just found myself there and never left, largely because as time went on there wasn't anywhere obvious to go to.
More than likely, if you've been on the road playing music for a few years, you've closed off alternative career paths, so you're possibly (more or less) left without many options.
After all, there's no superannuation scheme (and, more often than not, no health insurance) for musicians.
So, what do you do to keep it going? It seems like most of the artists I tend to follow seem to have set about transforming themselves into a cottage industry, and recent releases are often, it seems, an integral part of keeping something new as part of the stock on the merchandise table. Performance payments might keep the wolf from the door, but I suspect you need as many additional avenues to keep the money coming in so you can put food on the table.
To that extent, of course, it's handy to have something that'll work on a regular basis.
That's, I guess, the beauty of the Allman Brothers' New York run in March each year. The fans know to expect it, and can probably plan long term holiday plans around something in that general time frame. You'd make the actual bookings once you'd scored tickets, of course, but you'd have things in place so you could proceed from there once you had.