"Amazon lockers" are at places other than your home. So unless they're somewhere you're already going to be going, at the right time, for other reasons, that option is much less convenient. Especially if your other plans change and you now need to go out of your way to get your package.
But Amazon offers lockers for apartment communities. It's not a public locker, but if something gets shipped to your address it automatically ends up in the locker. This is very convenient, but the fact that it's offered shows how dominant their position is
