"Static site" is a bit of a misnomer, it refers to the webserver's view not the clients view. The client can still dynamically request chunks of information, favorite things, sorts things, save things between sessions, and form dynamic connections (though you'd need to point to a 3rd party signaling server for the WebRTC connection to come up).

I.e. it's not the web page that is static rather the files to host the web page are static vs say being a php site dynamically generating responses based on user/session/request information.

You could do everything but collaboration using a static site and localStorage though Apple's support of localStorage is iffy now.

You just gave two reasons why it wouldn’t work as a static site

That is indeed what I said