There are a lot of big organisations with big internal websites that were made in the early 00s. Indeed governments (and there are lots of them) that routinely put out invitations to tender that specifically mention that the site must work under IE6/XP but no mention of other browsers.
You can just pull the rug out from under them, but let's not forget that Microsoft makes most of its money from corporate customers, not from end-users. Pissing your customers off isn't a good way of making money.
I kinda understand that, but the problem as I see it started when someone promised backward compatibility. That's nice and all, and it made Microsoft what it is, but that's not the web. The web has no allegiance to no st!nk!ng backward compatibility. Its only allegiance is to standards. Yeah, I know they are shitty and suck (so say Silverlight disciples) but they are mine! And yours. ANd they are all we got.
The web. No entrance for:
1) Backward compatibility seekers. Just use a native Microsoft app already.
2) Lost pixel seekers. Use fncken PDF.
The two of you, I hate you