Even Datastar/HTMX might be too much. Server-side HTML can get you very, very far in most applications. It's faster, lighter, and looks and feels cleaner.
Case in point: do you really prefer a heavy, real time interactive message board like the default interface of Reddit? Because we're talking on HN, which is super fast, light, usable, and completely server-side.
HTMX is real time in the sense that it updates over the wire, but you're still keeping all state on the server side.
I don't want to reload the page to open a drawer. You'll notice HN isn't exactly mobile friendly because that requires hiding enough options that you need drawers or other ways to shrink and expand. You can do that with CSS, but that's still state, just state localized to that page load.
And there are sites that have unavoidably complex session state. You can have a resource that's on half the pages but is expensive to compute. I don't want to load it every time when almost none of it changes. I don't want to cache it on the server if it's a big payload
There's a world of difference between no state and over bloated SPAs
With .cljc files you can avoid the duplication anyway.