I don't think Microsoft will make the mistake of falling behind on the web platform again. In fact, their latest moves (both tech, organization-wise) show them throwing more weight behind IE/HTML and less behind .NET/SL/Win32 (this is from me reading the tea leaves from the outside, not any inside scoops).
I'd argue that MS is still falling behind- IE10 is just catching up but has no leapfrogging and how far out is IE11?
Even more critically, look at all of the users MS is leaving behind- no XP support for IE9, will they abandon Win8 users when there's still a massive number of them?
Unless IE ramps up their release cycle I see no way they can stay on the leading edge.
