IE7 Was released almost exactly two years ago and it already has 45% market share (compared to 25% for IE6). Next year it is likely that over 50% of users will have either IE7 or IE8. I think a slight majority of users will probably have IE8 in 2010, and a significant majority will have it in 2011. I expect Microsoft to push IE8 more vigorously than IE7 because IE8 is significantly more secure (on paper, at least) than IE6 and IE7.
You're probably right. What I really meant to say was that it will be at least 5 years before the numbers of IE6/IE7 are low enough that anyone can afford to drop support for them. We're going on 7 years of having to support IE6 (although some sites are starting to drop support for it finally).
