From time to time I see questions patterned like “why doesn’t Microsoft include X in Windows?” where X is some seemingly basic feature like PDF viewing, anti-virus etc. Surely Microsoft with its armies of programmers and war-chest of capital could buy or build a decent “X”? Well, here's the rub. Remember when Microsoft added a web-browser to Windows? The DoJ slapped an anti-trust suit on them, and the EU turned them into their personal ATM. On one hand what MS did was predatory and abused their windows monopoly - they didn't want to become disintermediated by the web browser, so they fought hard to own the browser itself (and were rightly punished for it). But because they got slapped so hard for doing it they now have to tread very carefully in the ways they extend windows. Whereas apple can turn ISVs who build on top of there software platform into roadkill Microsoft can't do that for fear of being slapped with a law suit, so instead they have to offer features they'd LIKE to build into windows as free downloads. When I started working at MS as a contractor one of my managers had briefly been on the team who built MSMQ (which ships as part of windows). He talked about seeing (in the late 90's) some very slick, robust stuff in the task scheduling space (not exactly sexy, but doubtless a worthwhile improvement to what built into Windows at the time). Apparently none of it saw the light of day because the companies lawyers said it was too risky to release.
If OSX ever became popular enough this would be a problem that Apple would have to deal with (and which they may yet face with the iPhone).