Maybe I am wrong, but what I read and observed from LiveView it sounds that your use case is a good fit for it.
But this doesn’t happen in every request. For what I understand just when it looses the internet connection, or its a new session.
How does your JS implementation differs?
For what I understand LiveView have hooks to allow you to do that.
For what I know LiveView doesn’t consume much resources, and it only sends the diffs to the client.
It sounds that you are already very familiar with the frontend complexity, thus not buying easily into LiveView, fair-enough 
