Managed to predict Microsofts direction before the 'Threshold' announcement, yipee !
How accurate is this (this was before threshold was even announced):
Metro\WinRT is not yet designed to replaced the desktop, does not have the professional app catalogue nor marketshare presence. In its current state it’s a tablet prioritising OS, released in haste by Microsoft to compete on touchscreen-centric devices. Its foundations are still largely being set.
Microsoft will continue to improve and update the desktop alongside metro. Ms may even make an enterprise/pro geared version of Windows x86 where the start screen is replaced by a start-menu of sorts. In addition to a dedicated, vetted, deskop app store. Though the WinRT runtime will still be available and metro apps will be able to run in Windowed mode. This would be required because in order to advance the desktop and introduce gestures, workspaces similar to OSX, the desktop UI would need to standalone, otherwise it would conflict with Metro and complicate\disjoint the user experience further. Only enterprise/industry/pro sector applications will be making their way there. Continued...
Read full post in this thread, towards the bottom. Link here.
In light of this:
Judging from some of the below comments, some people have wrongly perceived this move by Microsoft as giving up on Metro in the enterprise. On the contrary, it couldn't be further from the truth. First of all Microsoft never really expected enterprise to jump on the Metro bandwagon to begin with, but such a move (threshold) will allow the enterprise to start targeting the WinRT runtime and having those applications run in windowed mode, side by side with their legacy standard desktop ones and these same Metro apps will of course then also run on any other Windows version with Metro/WinRT runtime, so ultimately bringing enterprise/pro-grade apps to all its platforms (Since all have the WinRT runtime). Thus once WinRT has enough enterprise apps on it and UI/API's advanced enough, it can start deprecating the desktop in the enterprise too.