I mean App Clip is a replacement to QRCode App as a concept in UX, not the tech. And Apple will gain an unfair advantage now they have take this step before PWA were even ( if ever ) available.

Yes I agree Web Push is certainly a solvable problem. I have always maintain vast majority of Apps doesn't need to be a native app, some sort of decent Web Front End with sprinkle of Native functionality will do. Like most Web Forum, Stores' Front End etc. These business's App doesn't need Apple's curation and gatekeeping.