The question isn't whether or not carriers abroad support eSIM, the question is, can I, a visitor to the country who doesn't have a local address, local bank account, local government ID, and who may not speak a word of the local language, get a plan with an eSIM before I walk out of the airport?
It's usually easy enough to buy a physical SIM card when you arrive, some countries have vending machines for them in the airport.
I'm going to Turkey next year. According to Apple, there are 3 carriers there that support eSIM. Fantastic. How do I get one? The carrier's sites are in Turkish. I stumbled through one of them with Google Translate. I think I need to already have a Turkish number to sign up. I'd most certainly need a Turkish address, possibly a Turkish bank account to pay for it.
Hell, I went to see what the options are for the UK, to at least remove the language barrier. Seems like none of them support eSIM for PAYG. I guess as a visitor, I'm not getting an eSIM.
And yes, I know about Airalo and the like. They're convenient, but expensive compared to local plans. They also don't support voice calling if that's something you need. Airalo is probably fine for most people for short term travel, but if you're spending a lot of time abroad, it's not going to cut it.