The React team really does not like SPAs, which I think is a bit of a shame. I'm not a big fan of the mish-mash approach of client and server components that Next et al now encourage.
For the type of app that React excels at, or at least the type I like to build, the performance issues with a SPA aren't a big deal.
The hybrid server render, then hydration step is too magical for my liking. There's a bunch going on in there that would be very difficult to debug, if some mysterious error at this stage of the app were to present itself. I prefer either wholly SPA or serverside, can debug and understand the whole thing.
For the type of app that React excels at, or at least the type I like to build, the performance issues with a SPA aren't a big deal.