http://tools.ietf.org/html/draft-montenegro-httpbis-speed-mo...
They took Spdy and dropped priorities, settings and other ill-conceived parts from it and made compression and encryption optional. There's still some Spdy warts in the HTTP parts of it though...
So they prioritized different things. That doesn't make it much better.
As an aside, where is the Microsoft reference implementation of Speed+Mobility? Where is their browser support for it? This, like so many Microsoft initiatives, seems primarily intended to delay and divert an initiative to make the web better.
Rough Consensus and Working Code[3] built the internet, and it seems to work well enough to be useful.
[1] http://en.wikipedia.org/wiki/X.25
[2] http://en.wikipedia.org/wiki/Open_Systems_Interconnection
Further implementations can be credibly compared and considered. Many "HTML 5" features came via Google Gears, and would have taken a decade the traditional paper route.
As an interesting side note, tunneling HTTP over a random port (in the slides port 61985) had a higher success rate than port 80 (86% vs 67%). If I remember correctly, the speakers attribute this to intermediate proxies hardcoded to handle port 80, leaving other ports free of processing.
http://www.belshe.com/2012/03/29/comments-on-microsofts-spdy...