The universe is much bigger than the boxes of gas that you're used to doing in a laboratory experiment, ok? So it's not that gravity made the entropy of the big bang, at the big bang low. In particular, if you ask yourself, are there ways to arrange the stuff in the early universe such that the entropy would be much higher? The answer is clearly yes. And roger penrose, former mindscape guest, a recent nobell prize winner, was the one who really emphasized this, starting back in the 19 seventies. But he's emphasized ny times since then. A single black hole at the center of our galaxy has more entropy than the entire universe had