I think you underestimate how easy Apple has made it to switch carriers with eSIMs. I can have several stored on my phone and activate them with a few touches. Very consumer friendly, no need to go to the store or even shuffle SIM cards while taxiing to the gate.
So dropping the SIM in the US is more a consumer hostile move to save a few cents and force them to use the tech Apple wants you to use then anything else.
They can't do that in many other countries as neither carrier nor population where okay with accepting not having a SIM slot.
eSIM is easily usable in the EU many people still insist on using physical sim cards for various reasons, similar "unlocked" phones are the standard in many EU countries. I'm not even sure it's legal to sell carrier locked phones in all EU countries, I think it isn't at least in some.