No it's not. The percentage of people who actually can use alt stores is so small that nobody will really dedicate money to make browser build for iOS. Why would they when Apple would just make the work impossible anyway.
It's pure malicious compliance from Apple. Anybody defending Apple on this is simply delusional.
Browsers with alternative engines can be offered in regular AppStore. That's why I wonder why isn't this a thing. At the end of the day, browser makers probably want to reduce confusion and complexity of maintaining two vastly different applications under the same name. This most likely isn't a case of malicious compliance, you got yourself carried away here I think.
I think the main technological limitation is that other browsers cannot just-in-time compile (JIT) JavaScript or any other embedded language. Except in the EU.
ETA: your link includes JIT; I’m pointing out that that’s why they don’t exist outside of the EU. Non-JIT browsers would just not be very performant.
Now it's straight up protectionism from USA. You touch our tech margins, we won't do business with you. So yeah the regulators are unable, even if they wanted to something.
Doctorow is right when he keeps saying that countries should make it legal to jailbreak devices. The problem is that first country that tries that will get hammer from the almighty POTUS.
It's pure malicious compliance from Apple. Anybody defending Apple on this is simply delusional.