If that doesn't convince you to support HTTP/2, then nothing will: https://www.httpvshttps.com/ HTTP/1.1 is 5x-15x slower in this benchmark! These insane perf gains are possible only thanks to HTTP/2, specifically thanks to its support for multiplexing. Please read the spec and understand the technical implications before criticizing.
On some unrelated note: I found this tidbit of humor in the RFC draft (https://tools.ietf.org/html/draft-ietf-httpbis-http2-16):