Using JS on the backend costs more than it’s worth for most people to have this facility. Other JS frameworks/libraries have no problem working with views that were filled in server-side before taking over themselves. From what little I remember of Ember pre-1.0, it should in principle be able to as well. I’m sure much has changed since then, though.
If the only point is to pre-render the view, then it’s not a strong sell. There’s more utility to sharing code between the backend and the frontend when you’re using types to enforce invariants, describe valid data - JS doesn’t provide proper tools for any of this.
Ever wanted fork in your JS? GHCJS can do that :)
Other JS frameworks/libraries have no problem working with views that were filled in server-side before taking over themselves.
Which ones did you have in mind? Obviously, you can do whatever you want with jQuery, and probably hand-roll this logic with Backbone, but neither of those have the benefits of a full MV* framework like Ember/Angular.