That does appear to be the case, but it could be included in the libraries elsewhere in a Rails 7 app. I haven’t looked too deeply where Rails 7 or which library would pull those in. It could be Hotwire related as far as the way we should approach channels and broadcasts.
Personally, seeing ActionCable moving into a "background" resource that is consumed via Hotwire is a good thing. But for existing applications, we may still need to import in the custom channels that we used in the past which means that we would need to keep the @rails/actioncable library.