As a programmer, I absolutely hate SPA's. I've never used a good SPA, they're always slow, and behave strangely. I much prefer the traditional way. It's the same with Electron apps.
Agreed, logic usually ends up scattered between the front end and the back end. You need to start using JavaScript (I much prefer Python). The Angular app I ma maintaining just now would be so much simpler if it was server side rendered, instead we have an ajax call to load contents of every dropdown....
I think it's just web developers who like SPA's