That doesn't stop today's dynamically updating pages that also break the back button.

Frames also broke the back button when they were first introduced!

Together with the other early problems - ugly borders, proliferation of scrollbars, and limited browser compatibility - it meant that frames were seen as a usability disaster right from the start.

They never managed to fully shake that reputation even as browsers improved in the later 90s.

That ship has long since sailed. We live in a world of web apps with dynamically created content, AJAX, and so on. The main entry point for the app has a URL, and then within the app all bets are off. Same with framesets.

SPAs were a low point, but I've found consistent and linkable URLs has gotten better with developers recognizing the importance due to "SEO".

[delayed]

There se excretes to this, particularly if you value speedy vs delayed updates to your indexing