Preinstalled stores are limited to manufacturers and distributors and they suck, so nobody uses them. It’s pretty easy for someone with a tiny bit of tech knowledge to do some research and find out how to enable the ability to download APKs from the internet, but sadly, that’s not most people. Google doesn’t have a monopoly because Play Store is good (it isn’t), they have a monopoly because they’re anticompetitive.
I think the implications behind there being infinite time in the past are fun if you assume that the universe works like a stochastic state machine. It means that either every finite event that has happened and will happen has already happened an infinite number of times or the universe is infinitely large.