The thing that went wrong with front-end frameworks imho was that instead of being what was promised: you could update UI elements with NO NEED to contact the server at all, only posting back when something needed persisting, instead it became an excuse that every action on the front-end needed to call an API or 3 so we've ended up with over-complicated apps that instead of not relying on the backend are relying on it more than ever.

Any little glitch, slowdown or unavailability is affecting you not only once on page load but potentially with every single interaction. To make it worse, a lot of backend interactions are not made interactively or synchronously where the user might expect to wait a little while, they are made in the background causing all manner of edge cases that make apps somewhere from very slow to virtually unuseable.

I guess it's that old adage that people will make use of whatever you offer them, even if they go too far.