> Your typical SPA has loads of pointless roundtrips
This is an implementation choice/issue, not an SPA characteristic.
> there's probably ways to build a 'SPA' experience that avoids these too
PWAs/service workers with properly configured caching strategies can offer a better experience than SSR (again, when implemented properly).
> The high compute overhead...
I prefer to do state management/reconciliation on the client whenever it makes sense. It makes apps cheaper to host and can provide a better UX, especially on mobile.
As an issue, yes, often ignored by QA, Product and engineers
Except for a user on a lower specced device that can’t performantly handle filtering and joining on that mass of data in JS code, or perhaps can’t even hold the data in memory.