Bill Gates announces that the release of Windows 7 will be in 2009

Last Thursday April 4, Bill Gates was at the annual conference of the Inter-American Development Bank in Miami.
A question posed during a seminar about the philanthropy of company, the cofounder of Microsoft answered that a new version of Windows, the 7th with the name, would be released during 2009.
Initially it was foreseen for 2009, then pushed back to 2011 and then supposed to come out in 2010, Windows will apparently be released next year. Microsoft is not accustomed to advancing its release dates... What can this reversal of date mean?
Windows Vista, released at the end of January 2007, did not have an outstanding success, its sales more due to OEM licences than deliberate adoption by the users, this announcement reveals the very negative perception of Vista. Indeed, if one looks back to previous Microsoft releases, one finds a certain similarity concerning the transition between Windows 98 and Windows XP, two systems with uncontested commercial success. To calm the shareholders and satisfy "Windows addict", Microsoft released Windows ME in September 2000, a heavy and not very reliable Windows 98 version. Releasing Windows 7 "only" two years after Windows Vista would prove that Vista is nothing other than a stop-gap version released to calm the investors... Moreover certain functionalities initially advertised to be part of Vista have not seen the light of day, such as the file system WinFS that will appear in Windows 7.
For us, Mac users, the release of a new Windows system is without interest. However, with the enormous development and financial resources of Microsoft, this Windows 7 could become a real competitor of Mac OS X in term of stability and user interface. This would endanger the weak interest to switch to a Mac that has been seen these past years, since the dissatisfaction felt by the PC users could cease.
Such a situation would act as a brake to Apple as it struggles to increase its market share. How would Cupertino react when faced with such a situation?