That's a good breakdown of some of the specific differences, and I can think of others. (That's why I opened by saying I empathize with people who think Apple should do this in a way that attracts even more developers.)
Depending on what you mean, I might disagree with "no background sync" (you can, of course, keep state consistent between devices with the aid of your web server's own version of what happens with iCloud or whatever else), and of course a Web app can know whether it's running as an "app" and choose to tell the user that it's possible. And to agree with you, a bigger part of an iOS app these days is its presence across the system, like in widgets, shortcuts, Siri's knowledge of it, and so on – and Web apps aren't really iOS apps in that sense.
But I've gained the impression that largely, the developers who are unhappy with iOS's App Store just want to have apps in the traditional sense across platforms – iOS, Android and possibly "other" – and that many of these would be totally viable as Web apps in today's environment.
And here I'm just responding to people who are saying developers are forced to release iOS native apps on the App Store because there's no other option.