I didn't know app loading screens were "a great feature".
Anyway I really don't see the point of PWAs or much future for them anyway. Even if Apple started supporting these with Safari, the web apps still could not interact with different hardware components/sensors, iOS SDK's etc.
React Native already brought a platform which allows making apps with native components and good performance with JS + decent access to hardware and iOS and still it's barely used outside of hobby projects.
I'm sorry, but native apps aren't going anywhere.
It's used in a lot more than just hobby projects.