Apple declined to implement 16 Web APIs in Safari due to privacy concerns

There may be some legitimate fingerprinting concenrs. But given the list of API's it's hard not to see this as Apple crippling PWAs to prevent them from replacing native iOS apps (and hurting Apple's revenue from the Apple tax).

And maybe I'm missing something, but wouldn't the fingerprinting concern be mitigated by the fact the app has to ask for permission before using the API? If an app that doesn't have to do with MIDI asks for permission to use my MIDI device, I'm going to be instantly suspicious.

Exactly. This is about making sure web apps are not as powerful as native apps.

One thing is the revenue generated by the App Store but suppose JavaScript web apps were just as powerful and well integrated as native apps; then why use native apps at all? Why have an App Store at all? Why have a Mac or an iPhone if any device with a modern web browser would do?

When Huawei tried to create their alternative to Android. The big thing missing wasn't the hardware or the operation system. It was the App Store with your map app, your banking app, your scooter app and so on.

The App Store and the proprietary development platforms for Android and Apple has become a way to keep their duopoly in place.