WebGPU and WASM are last on my list of things that are missing from PWAs on iOS. Native integration into the rest of the OS both on a UX and functionality level is much more important to me personally.
This includes things like background data pre-fetching (e.g. for a read-it-later-like app, I want all my articles to sync so that I can read them on the subway without network coverage), offline/local notifications (e.g. for a to-do list), proper backup support (all my PWAs get their local state wiped whenever I switch iPhones!), access to the local file APIs (both as a provider for things like Dropbox and as a consumer for things like document editors) and much more.
There are many apps that already don't need any of these, though. Most airline, ticketing, hotel, shopping etc. apps should really just be PWAs at this point.