Most of the apps I've worked on were very business oriented, and about people getting work done, rather than "website" type stuff that's mostly static. So for example, being able to refresh a part of the screen with new information from the server, is critical. Doing page reloads would destroy the experience. I have 35yrs exp so yes I've used most of what you mentioned.
I just use the 'fetch' command to get data from the server. That's basically like Ajax. Where React comes into play of course is taking care of all the page updates, which would be a nightmare for any large app, unless you have a framework being used.
