Maybe your prediction is informed by different internet usage scenarios but for general mainstream web surfers, I can't see how the industry will migrate back to server-side rendering in 3 years.
The unavoidable technical issue is the round-trip latency of the network. The same delays from the speed-of-light will still be there in 3 years. Most of the world is accessing the web through mobile phones which has worse latency than desktops. Server-side rendering (which means painful page reloads) is user hostile on slow network connections.
I’ve found many sites that use frameworks like react to be much more user hostile, particularly from a performance and accessibility standpoint. The reddit redesign comes to mind. It’s so much slower now than it used to be on a browser (perhaps they’re intentionally doing this to push people to their mobile app), that it’s noticeably reduced the quality of the experience.
I guess I just don’t understand how people see page reloads with proper caching as unacceptable from a performance standpoint compared some JavaScript app maintaining a virtual DOM, which is also likely regularly communicating with a server.
How easier? By dint of additional JS that an SSR doesn't have/need? Not sure how pulling a header nav (or any cell/element) from a server on pageload plays into that, but even today I've watched sites (plural) loading, pushing loaded parts all over the page for 30sec until everything settles down. Maybe blogs aren't quite so affected by this set of popular dark- and anti-patterns, but even so the post is almost always the last thing to load. Presumably, the monetization and data collection takes precedence over all else.
So is downloading an entire app when you only want to read one page.
Svelte also extremely promising. It brings a brilliant hybrid solution to the table.