That is an illogical conclusion. That makes the assumption that they would all have a relative fundamental basis for rules. If there were parallel universes and one of them did not allow travel to others you could not get there. Instead you could only travel to those where it is possible to move between them. Sort of like, if you build a bunch of rooms but a few have no doors or windows. You must use a door or window to enter the room is it possible to enter one of the doorless/windowless rooms? The answer is no. You would instead enter a room with a door or window because they have to be there first to open. A better example would be to place the doorless/windowless room on the moon and the room you start in with a door in Florida. They don't touch and have no way to connect because there is no connection other than they exist.
Just remember that it's really only a hypothesis since the math involved doesn't quite work. It is just as likely there are no parallel universes and this is in fact the only one that exists. In fact right now to the best of our knowledge they not only don't exist but can't. Of course this is all subject to change, maybe. The original idea was really just an intellectual pursuit question not something that was supposed to be taken too seriously. Designed instead to provoke thought and discussion. Really, it's just one big "what if" scenario.
There is the idea of all said universes being connected into a multiverse in which fundamental rules and such are set by the whole rather than each individual alternate world.
The Set "multiverse" contains all other sets and all sets within set "multiverse" follow all fundamental laws of the containing set.
But honestly who does
The realization of the first condition precludes the possibility of the second.
The Set "multiverse" contains all other sets and all sets within set "multiverse" follow all fundamental laws of the containing set.