It's not just funding. Apple changed webapps to delete indexedDB periodically even if they are inatalled on the home screen.
There's no way to have a great experience if you can't store data permanently.
I am pretty sure most apps use AT LEAST iCloud to store data
Modern web apps can cache all the files they need to function. They can work offline. So when iOS deletes a web app's data, it doesn't just delete some content and maybe a few settings. It's basically like it deletes the entire app and you have to reinstall it (by opening the web app and re-download all assets that make it work). Sure, the icon is still on your home screen, but the entire app behind it is gone.
It'll also delete things like your login status/tokens/etc, so you have to log in again, maybe the web app has settings that it doesn't want to sync across devices, etc.
I assume that when Web Push hits iOS, notifications will only work as long as you open the web app often enough.