Despite advance notification and a desire to cease support for XP, Microsoft found itself in a challenging position: completely bail on said OS and/or provide a security-patch for IE (that was so paramount that the American, Australian and British governments all advised their internal end-users to cease using it… until said patch was actually delivered). Kudos to Redmond for coming through. Nevertheless, the firm has a long way to go prior to when their ultimate dependence on Windows will cease (which at this juncture seems highly unlikely)… if it ever will.
(Source) Sydney Morning Herald: http://goo.gl/M1i9aN