Future? Looking at some of the examples, this seems a lot like the same old web server frameworks we had like 15 years ago, maybe more. Granted they didn’t have SSE but regardless the DX was pretty bad. I don’t see a compelling reason to go back.
I feel if anything Datastar is targeted ad veteran devs who are done with endless ecosystem churn, who want to use their favorite backend language and to make performant fullstack realtime collaborative apps.
If you haven't run the gauntlet you probably won't see the appeal.