And while we're at it, how come if I have a phone without a sim I can't at least navigate to a carrier webpage to buy an esim?

The phone could pop up a menu saying "Here are the available networks", and you pick one, connect and it says "Welcome to AT&T, enter credit card number here", and you type a number and hit OK and you're connected.

Oh wait - just like Wifi!! Why are mobile networks so far behind?