Viewing a web browser as the “open internet platform” is the crux of this issue that has gone unchecked for years. We turned a document reader into an application environment. This is the issue I have with PWA. A plastic bandage on a festering wound.

On your points regarding sandboxing, I believe that should’ve been rolled into OS userspaces for years as well, and only developing the technology as it relates to web browsers is a huge oversight that has and will further lead to security issues.

Not everything needs to be an application but building applications in a document viewer is a bit silly.

edit: less cynicism; I want to take a moment to charade all the efforts gone into Linux distributions that take sandboxing and immutability seriously. They aren’t very good solutions either, but it all starts somewhere.