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.

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.