It’s difficult to keep a band together. Period.
It is the nature of the beast.
When players are young, there’s a lot of youthful enthusiasm and energy. And, often, drugs. It’s difficult to push the wet rope of discipline and dedication with guys who find that kind of stuff “boring.”
From personal experience, I remember one of the guys in a band I was in getting pissed when I emphatically asked everyone to show some professionalism after a gig, and get busy loading out of the venue. The guy in question (a longtime friend of mine) got in my face and snarled, “Why are you telling anybody what to do? Who made you boss?!”. I replied, “You wanna be boss? Cool! Then you wrangle these guys to quit fucking around and do what we came here for. ‘Cause I don’t want to spend the rest of the night here. Do you?” That did the trick, and things went much smoother from then on.
With later bands I was in, the issues of personality conflicts, lack of practice discipline, yada, yada, yada all came into play at one time or another.
With even older band members, issues of time priorities will inevitably arise: the band is a lark, something fun to do…life and mood permitting. Generally speaking, gone are the youthful (read, unrealistic) fantasies of stardom. It’s more of a “we’ll do it when we do it” kind of thing.
Now, this is isn’t to suggest that all later-life bands are like this. I realize not all are. But given the odds, many will be.
The point is: It’s hard to find/join/assemble the perfect combo of players to form a band that suits everyone’s personality, goals and schedules. And, if you do, it most likely is guaranteed to be a chore to keep everyone together/on the same page/satisfied as the band evolves.
At least, that’s been my experience over the decades. Just look at the vast majority of major, major bands throughout history. Band casualties are virtually always inevitable.