> "automatic state syncing and zero UX degradation" is a "draw the rest of the owl" exercise

That's an assumption you're making, but that doesn't necessarily have to be true. I offered you what amounts to a magic button (drop this script in, done), not a full implementation exercise.

If it really were just a matter of dropping a 50kb script in (nothing else) would you do it? Where's the size cutoff between "no" and "yes" for you?

> Everything is domain specific when it comes to sync-based latency hiding techniques.

Yes and no. To actually add it to your app right now would most likely require domain-specific techniques. But that doesn't imply that a more general technique won't appear in the future, or that an existing technique can't be sufficiently generalized.

> the extra 50kb gzipped is starting to feel kind of heavy

Yeah - but we can reasonably assume it's a one-and-done cached asset that effectively only has to be downloaded once for your app.