One thing that really bothers me is that there is no install prompt for a PWA on iOS. Users have to be told to find the install button which is buried in a menu.
I would also like to have it, but I can see how it could become a spam issue. Every garbage site on the planet would start pushing PWAs to get on a users home screen. It would be the same thing if notifications were reserved for PWA installs only and not in the browser.
That's one area where the app stores are pretty good. If you open the app store, you want to install apps. The same can't be said for a website.
I think the only way it would work really well is if the add to home screen / install button was prominent in the browser chrome and sites could trigger some effect if they can be installed as a PWA. For example, change from an inactive button to an active button.
