So in a few years from now, you'll be supporting one version of Chrome, one version of Firefox, one of Opera, (probably) one of Safari, and ten versions of IE.

So in a few years from now, you'll be supporting one version of Chrome, one version of Firefox, one of Opera, (probably) one of Safari, and ten versions of IE. I think the nightmare scenario couldn't possibly play out this way. We've all seen what really happens when there are too many browsers to support; web developers drop all pretense of supporting the least popular browsers, which would in a case like this be Opera, Safari, and maybe Chrome. And sites put up banners telling users to upgrade to the latest version of IE.