I remember when the point of an SPA was to not have all these elaborate conversations with the server. Just "here's the whole app, now only ask me for raw data."
That was indeed one of the main points of SPAs, but React Server Components are generally not used for pure SPAs.
Correct, their main purpose is ecosystem lock-in. Because why return json when you can return html. Why even build a SPA when the old school model of server-side includes and PHP worked just fine? TS with koa and htmx if you must but server-side react components are kind of a waste of time. Give me one example where server side react components are the answer over a fetch and json or just fetching an html page?