There is plenty of speculation as to the release date for Windows 8 but it is simply speculation. The only people that know for sure are Microsoft and their usual comment is 'it will be released when it is ready.'
I guess Win8 will not be released on 2012, otherwise Win7 will only be considered as a transitional OS (like those of WinMe or Vista).
Users will loose confidence in using new MS Windows. It's hardly for users to manage with such a short life of OS.