Presuming you've done the research here: will Websocket-over-HTTP2 make websockets cheaper, to the point that e.g. it'd be performant to use individual websockets for each channel of a pub-sub system, rather than multiplexing them all over a single channel that is statefully subscribed on the server?

Or, now that I think of it, would the modern recommendation for this lean more toward opening multiple parallel Server-Sent-Events streams, with each channel being its own HTTP resource? That seems more idiomatic, at least.