People aren't doing this on the web for it's ubiquity, they are doing it because application distribution in the non-web ecosystem sucks. And because as bad as HTML and CSS is, native UI frameworks are even worse for most use cases.

If you don't like how all the applications are built on the web, by all means, provide a native alternative that's better.

Microsoft under Ballmer would have loved something like that, and spent a lot of money on trying to beat the web.