What's missing until regular websites have parity with mobile apps in functionality?
- Accelerometer and all sensor support (some of these are already supported on various browsers on various OSes)
- Background support
- Bluetooth
- WiFi
- Better notifications
- etc.
Sure there will always be a need for native, but 99% of apps don't need any of that stuff, really. Though I suppose both Apple and Google have an inherent interest to gatekeep.
Looking at my own most used apps:
- Messenger
- White Noise
- Teams
- Google Maps
Literally all of them could be implemented as responsive pages with acceptable performance. There are a small number of companies that don't bother with mobile apps, Craigslist being the most notable of them until a few months ago. Part of the issue though is that the app stores give you a lot of visibility and to get that visibility you need to be in the app store. Sure you can use a web view, but in some ways that's even worse than just a responsive website because now you have to deal with the abstraction of your site that is a WebView. Not to mention the temptation to try for "best of both worlds".