this is always such a grimm, yet fascinating topic to speak on.
JP won't quit. He is commander and chief of that band, and I judge him to be someone to respect a system of checks and balances within the band's operations in order to keep the ship afloat.
But if all of a sudden, James John Mike and Jordan were no longer on board, I couldn't see him scrambling to assemble a new Dream Theater. I think he'd feel like there's a serious loss of dignity to be suffered in doing that. However, if the members left one by one over the years on good terms... and the band was with him to agree to push through and bring on a new member each time, I could see John carrying the band into the 2030's with a lineup consisting of 4 new bandmates. I'd say "JP won't let it go on without Myung," but if Myung quit early enough, I think JP may want to get a few more tours in to support himself and family. Or not?--I mean, what do I know. You just Can't forget the fact that Dream Theater is a source of income for the guys though.
I think we could see a farewell Jordan tour one day. I mean, he could just up and leave on a shorter notice, but I don't know if he would. He's the oldest by a bit, and might have to just retire from touring one day and insist the band go on without him. 'Come See the last Tour with Rudess!' - that would probably be a decent marketing scheme.
They're only human. They have monetary needs like the rest of us. And I judge the current members of DT to all be less dramatic than Mike Portnoy. I mean, systematically put the band on hold for 5 years (or even 2 years), that's a pretty drastic and dramatic suggestion. Kinda like just trying to make the story of Dream Theater some sort of movie script. I guess I still can't get over how bad of an idea I thought that was.