It’s not that the others have many possibilities if the EU should remain in the current structure*. When the UK get’s a new treaty with even more cherry-picking (part of the common market, but outside of the legal framework) more countries will leave.
I wouldn’t underestimate the inertia, the political union has a momentum of it’s own**.
* meant as a statement, not endorsement - my POV is not important here
** e.g. many careers in Brussels : )
