I have no clue if Infinitelism as a term will take hold, but I'm completely certain that the philosophy behind it, or something similar, will dominate if we don't go extinct first. My reasoning for this is that we currently believe in two types of worlds. The first kind is what most of us think of as religious; a world where everyone is working towards some nebulously defined goal or serving some nebulous being. They're falling out of fashion as people begin to realize that these beings can't exist and that the people they're following are humans like themselves. What's replacing them are what we think of as secular worlds; worlds that work towards peace and contentment for all of the members, with the idea being that at the center is a world where everyone's happy. The thing is, that world doesn't exist, and in fact it can never exist. We figured that out pretty early on, and the past few centuries have been centered around trying to convince people that there is such a thing as paradise on Earth only to then fail in spectacular fashion. That means that there's only one option left; find an ideology that most of us agree is reasonable and then work like hell to make it as real as we can. Regardless of if you're one of those people who believes in physics, that's the only way our world is going to go. We can't have paradise, and no one wants to live a world they can't change. Whether the people in charge like it or not, our future will belong to everyone.