1. Average consumers are not going to install your PWA. I am sorry. Get over it. Geeks and power users maybe, but for the average consumer if you're not in the App Store and Google Play then you don't exist. All further discussion is academic/hobbyist.

2. Even as a developer, I reasonably expect to migrate or re-write an app after 5 to 10 years. If I wanted to work on mainframe or AS/400 systems, then I would do that. But not trying to maintain a mobile app for 30 years without any significant evolution is a feature, not a bug.

3. Even if I did crave multi-decade stability, I would feel no envy toward SPA web frameworks on this front.