I know, that's what I am suggesting should change in version 2.0. It is a widely supported popular extension that solves a major pain point for Git, most vendors have adopted it.
New things can absolutely be required as part of a new protocol version, in fact this blog post lists several new things that will be new in 2.0 and beyond.
The analogy I'd use is HTTP/2 and SPDY. SPDY started out as a Google produced extension to HTTP, gained popularity, and was then standardized/merged into the HTTP/2 standard. All I am suggesting is Git LFS receive the same treatment.