The SPA movement has always seemed like a cargo cult to me. Yes, AJAX is handy and it was exciting when it came out. We used it to update search results when you changed a filter.
For 90-95% of applications, a single page app architecture with a front-end JavaScript framework running a bunch of application code and rendering output is overkill and you could write the same app in half the time using server side rendering.
A (the?) primary argument for SPAs is state preservation/management. If you're actually building a web "application" (as opposed to web pages), then the default state model that a web browser provides is pretty bizarre when you think about it.
But then we wouldn't have the ability to build cross platform apps in HTML/CSS/JS. I'm working on an app that is built on Ionic (packages app for various platforms) and Electron (primary deployment model for desktop utilized by Ionic) that would not be practical if we were stuck on a server side rendering paradigm.
I can use HTML/CSS/JS skills (and Angular) to build a serious business application that runs anywhere and looks the same on each platform (or morphs to the platform UI if I care about that).
For 90-95% of applications, a single page app architecture with a front-end JavaScript framework running a bunch of application code and rendering output is overkill and you could write the same app in half the time using server side rendering.