The problem is, that except a tiny fraction of developers no consumer cares about their browser as long as it just works. There is no reason to switch. A browser is simply a browser no matter what its name is. All seem to do the same. The most common reason people activly change their browser is, as far as I noticed, because it's a new trend (firefox and now chrome).

And noone can blame business, that it doesn't dare to loose a significant amount of customers by not supporting IE with their website.