Why would it not be possible? Theoretically, the multiverse should operate by certain laws. It would be possible to work around those, if we found out what they are.

No, because it means that every possibility of humanity in an individual universe having progressed in a way that allows for interdimensional travel at any specific point in time, and the accompanying visits to other dimensions should constantly flood every single system with interdimensional visitors.

No, because it means that every possibility of humanity in an individual universe having progressed in a way that allows for interdimensional travel at any specific point in time, and the accompanying visits to other dimensions should constantly flood every single system with interdimensional visitors.

I can dream okay?

That's the thing. If every possibility exists, there should be a possibility for every universe to visit every other universe at every moment. But that would eliminate the possibility for a universe which you describe, where nobody travels to. The idea that every possibility exists is inherently paradoxical.

Really though, multiverse theory doesn't mean every possibility exists, due to said paradoxical situations and the fact that every possibility of every person entering every universe at every moment should exist. Rather, look at it as a range of numbers. If you count only every third number, you don't hit every number but still have an infinite number of different possibilities.