I think MS was too focused on the web developer wishes while ignoring show stopping user experience complaints. Imagine if VS2010 still had those fuzzy fonts. I suspect most would still be with VS2008. From what I know fixing the font issue is possible with not too much effort but it should have been done before release due to first impression being important.

After that, users either chose to stick with IE8 or move to other browsers, leaving IE9(+) at marginal importance.