When I started programming, one had to repeat in Assembly the same application for each computer brand.

We are not that bad nowadays, it is a skill issue.

There are plenty of ways to have portable applications with native UIs without shipping a browser.

Somehow we managed to do it for decades and without AI writing the code for us.

If you want to ship a browser, I already have one, thus standard Web, with a daemon if it really must be.

I agree on the standard web point, but you still failed to reply to what is a native UI for every OS.

Portable frameworks exist, but they are at most native to a single platform.