I suspect a lot of these people are in the OSS hacker demographic (in my mind this means a college student running linux with lots of free time), in which case, why would you bother getting a Mac?
It appears lots of Android devs are exactly in the category you're talking about:
On experience of developers:
We can also quantify the signs of Apple’s allure towards experienced PC and Internet
developers, since the iOS platform attracts significantly more developers with sevenplus years PC/Internet experience, compared to other platforms. This confirms that
experienced software developers are moving into mobile, using iOS as an entry
platform, in what we believe is driven by the sudden rise in demand for developer
talent, especially in North America.
Since launching in late 2010, Windows Phone 7 has done pretty well in attracting
seasoned developers. We see experienced mobile developers coming to Windows
Phone, with a significant bias of current Windows Phone developers having between
three and six years of mobile experience - an indication that Microsoft’s strategy to tap
into PC and Xbox developer segments is paying of
