Facebook used to be server side PHP and it always was personalized. I think the distinction is more about the degree of interactivity. Highly interactive GUIs (the hell of jQuery developers) went to SPAs and are called webapps. Low interaction GUIs could be server side rendered with the technologies of 20 years ago even today. Most banking sites are low interaction and could be old style Java even if almost every one I see is a SPA now. The distinction is very fuzzy.