> In theory, with an eSIM it's even easier to swap in your old SIM because you don't have to deal with the physical SIM card.

But dealing with the physical SIM card is the thing that's easy. People already know how to move a physical thing from A to B. Figuring out how to electronically transfer an electronic SIM is necessarily less easy, even if we lived in a fantasy world where operators all cooperated to try to make it as easy as possible to switch to a competitor (heh).