Multiplexing is completely different from keep-alive. With http2 a web browser requires one tcp connection per website as communication is in parallel, approaches like conncatenating several css files into one have no use with http2 anymore! Http1 keep-alive allows reusing the same tcp connection for sequential requests/responses only.

Oh i know, i just don't think it helps in this situation, as waiting on the tcp connection is not the hold up in this situation.