Which begs the question...what would’ve happened had Mike left at that point?
"What ifs" are always dicey. My first impulse is to say that Mike simply never would have followed through.
But if he *had* somehow, my guess is that, had everything else gone down the same (Carl leaving the tour seemingly temporarily and then his passing several months later), Mike simply would have re-appeared in the band once Carl had to leave.
The timing of that letter to BRI isn't known. Was it before or after Mike had tentatively secured David Marks to come back? Was it before or after his own company had taken over producing the live tours?
It's interesting. I'm not sure how many times Mike ever floated/threatened to leave the band over the years, but I'd say his possibly quitting early in the 2012 tour (as described in his book) was a situation where he would have had far more leverage than in 1997. In 2012, the entire marketing hinged on it being a "reunion"; one of the core four guys quitting would have caused major problems. Whereas, in 1997 the tour was kind of running itself. Could Al and Bruce and backing guys have done a BB tour? Yes, and surely they would have added a few extra people. Would that have worked long-term? Much harder to say.
Don't get me wrong, I think Mike considers himself as having such strong ownership of the BB name that I'd say most any "threat" to leave, or quit touring, etc., would be pretty empty. I don't think he'd ever willingly give it up.