We are talking to a wall...you have no experience of E-Sim providers, and just focus on the theoretical advantages of the E-SIM (on which I fully agree).
uh, I am American, lived for 32 years in the US, where theory is put into practice in the name of progress and convenience. I've had phones with Sprint and Verizon, which are not eSIM (since such a thing does not yet exist), but rather CDMA. The eSIM as Apple proposes would still be GSM, and simply eschew the physical media.
You and your "we" are thinking inside a box, in which current standards and practices are hegemoniously locked into place while new processes and standards are considered, and you can't see outside of your confines to embrace a better system because you just accept the way things are.
Apple is fighting, in the big picture, to eliminate the SIM and adopt a new standard. Any carrier that accepts the standard would follow the rules, supposedly, by not blocking your switch to another carrier. In fact, the standard would provide for authentication via predefined keys, which would be stored in any of a number of ways, such that physical media wouldn't be necessary. It would be as simple as signing up for a service at the time of a carrier search, much the same way you log into public wifi services. Your account and credentials such as credit card would be stored with a third party (I'm sure Apple would love this to be them, utilizing your Apple ID! But it could be PayPal, eBay, amazon, google, etc). It's really as simple as that.
And viola! The theoretical becomes reality. Isn't that how it usually works?