H. Beam Piper touched on this in his first “Paratime” story. In this, there’s one time line that has learned how to transition to other time lines, and they use this to search for useful resources and technology. But when they’re coming back to their own time line, it has continued to split, so they see a “broadening of the bands”, where every time line is “theirs”, just slightly different based on choices made while they were away.
He kind of drops this idea later on, because of the implication.
Why? We already know the universe is infinite. This just means that it’s even MORE infinite than we thought; but since all infinities are the same size, it doesn’t actually change a thing.
