It's chemically inert like aluminum (after oxidizing, e.g. foil), so the processes acting on it are mechanical and subject to probability.

Some amount is going to be abraded, buried, etc, but you only need a few pieces to remain. Given their ubiquity in our culture, there'd be some somewhere.

Yet we can barely imagine a society without wheels, but some human cultures in South America didn't get that idea.

Assuming that every civilization invented glass is very tenuous.