Imagine if this was reversed and mobile apps suddenly started switching to SSR. Instead of downloading the app once and making lightweight JSON requests (analogous to what SPAs are doing), they froze for seconds while the next page is rendered on the server while losing all of the local state that you had typed in. Sure would be a lot of hate for that when they have been working fine for a decade. You'd probably argue, that it sounds like that is just a bad implementation of SSR. Not all SSR is like that surely?

This is how silly this weekly SPA vs SSR debate is.