XP on MACS...

Although, the difference is that Nintendo is not in the PC building industry, and thus can do whatever the heck they want.
The problem with Apple innovating is that lots of their innovations are similar to Microsoft's "innovations"; both can cause huge - and sometimes bad - disruptions to what could otherwise be a very comfortable future for PCs.
An example of such behaviour is here: http://www.howtocreate.co.uk/operaStuff/acid/
IE is different, but it is different in a very non-standard way. As a result, Opera 9 may very well pass the Acid 2 test, but web sites tailored specifically to IE will still have trouble with it.

Disrupting and innovating the personal computer industry can have very rough consequences for everyone, and it is usually not worth it.
Microsoft's move from NP-API to ActiveX for web plugins (done in IE 4, I believe?) was one such innovation that did not actually change anything for the better; it simply complicated the Internet.
(In fact, in my biased opinion, NP-API's ease of use and superior documentation makes it far better than Microsoft's precious ActiveX, and I'm sure it would have the same useability allowing for it to actually behave as a Windows component had Microsoft continued to support it).

Now, here's one reason why Apple could be seen as a bad thing:
They are severely limiting the expandability of personal computers. They may very well have a good OS (and I won't deny that), but the things have one single bay for CD/DVD, and nothing else. No floppy drive (which reminds me: What about Windows's preference to use floppies for boot disks?), no extra bays for when some new portable data storage technology pops up,

Thus, both Apple and Microsoft are killing growth in their own little ways.
Apple does it to hardware, MS does it to software.