> rather than the concept of SPAs as a whole.

This is the whole concept of the SPA - make a page behave like multiple pages. The premise itself requires breaking absolutely everything assuming that content is static.

> There's also huge benefit to being able to depend on clientside state. Especially if you want your apps to scale while keeping infra costs minimal.

Um... I'm old enough to remember the initial release of node, where the value proposition was that since you cannot trust client data anyway and have to implement thorough checking both client and server side, why not implement that once.

> I get the frustrations you're talking about, but almost all of them are side effects of solutions to very real UX problems that couldn't be solved in any other way.

Let me introduce you to our lord and savior native app