Modern IE is actually pretty respectable. Its biggest issue is that unlike its competitors, it only works on a single platform.
Just because it's not packaged as Safari doesn't mean it's not available.
For all practical purposes, Safari is an OS X-only browser.
Whether it's popular on Windows is also irrelevant with regard to the fact that it does, indeed, work on Windows.
Windows Phone uses Trident + Chakra for its IE deployment, as well, so if we're going to make that argument, then IE is multiplatform, as well :P
1. Within reason, of course. It's not on my router (but maybe it could be)