unfortunately HTML didn't make any significant progress as a hypermedia for a decade and a half, but some folks (myself included) are trying to fix that (unpoly, htmx, hotwire, etc.)

an enhanced hypermedia model offers a lot more interactivity often at a fraction of the complexity, and w/ the benefits of the REST-ful architecture (flexibility, etc.)

to draw a desktop app analogy, I guess these things need a back-end as a GUI application that has to deal with all the presentation logic, and thin client that remote desktop to that. While the current SPA model would be RPC with fat clients, your call.