I don’t see it withering away anytime soon. My entire career has been enterprise web development (which is why I roll my eyes at all the web dev rants). Every company I’ve worked at has used Java on the backend and some JS framework for the frontend. Java has only been improving in that time and getting much easier to write. I don’t see companies taking an (in their view) unnecessary risk that makes it harder for them to hire and lose efficiency, at least in the short to medium term.
I think the only way that changes is if developers are interested enough to try Rust, or any other language, in their free time. If they like it enough, they’ll suggest it at work. If enough developers are doing that, it’ll slowly shift the local scene.
Apple’s implementation of other PWA standards requires an app to be opened from the home screen. A user can’t access features of the app if they can’t add it to the homescreen.