A PWA running in a browser engine that they can’t control can have access to features that they can’t vet and restrict. If PWAs aren’t restricted to 50MB of storage and have near feature-parity with native apps then they’ll eventually lose the ability to enforce their revenue cut on In-App Purchases.

Not sure how it works on android, but on iOS I’m pretty sure this means that mobile game devs will start shipping games as WebGL/WASM with asset streaming and implement their own payment channels for micro-transactions.

Apple can’t risk it and I believe they will fight it tooth and nail to the bitter end.