Interestingly, we are, and have been, at a point were you can publish applications that run on any OS for a while, with PWAs.

There are very few software examples, that couldn't be distributed as PWAs, including secure things like banking, etc. With WASM in the mix as well, theoretically the sky should be the limit.

Even more interestingly it hasn't happened - mainly because Apple and Google haven't got behind PWAs for obvious reasons, so the app ecosystem just doesn't exist. It's hard to see how this will changes, when mobile operating systems are dominated by two players, with very obvious incentives to make things worse for consumers but better for themselves, by grabbing as much control of the apps on their system as possible.

If banks were to offer PWAs, they would probably demand something like Google's Web Environment Integrity proposal - or would be convinced by Google that they need it.