All a symptom of the browser being a document-first platform that's been reused to be app-centric. I agree with you it's a bummer that these things are getting reimplemented on top of a platform that already offers them, but the way the platform offers them hasn't changed much since the 90s and hasn't kept up with what apps need.

The core issue being that you have no way of statefully going from one page to the next. State only exists within the page you're on. Hence the rise of SPAs.