As far as a Mac being better for graphic programs, that is only marginally true, there are some color calibration matching stuff that is built into OS X that I don't think is in Windows. But overall you can make Windows do whatever OS X does for graphic programs. Now the apps for OS X may be a little nicer to look at an use, but that is probably more of a personal preference type thing than a fact.
I believe at a former time, Apple's "Color Sync" was considered a far superior system of color management than was possible with Windows. Adobe's "RGB "1998 is very, very, good, and since Adobe has a respectable market share of Software in the photographic and graphics arts arena, there should be very little difference in the results obtainable with either system. Here is where, I believe that habit may be causing the reverse of Windows dominance. I seems to me, many in the graphics trade are used to Mac, thus continuing to use them. This makes sense in the fact that it seems no one wants to have a new OS summarily inflicted on them. Resistance to XP and now resistance to Vista seems to make my point. But, all imaging hardware such as printers, tablets, and scanners seem to be available for the Windows platform, if not especially for the Windows platform. Many FX houses have written custom software in the course of their business, and so leaving Apple for the PC would be a major shock to their "system", if you'll pardon the pun
Once a particular system is in place, I think it's much easier to call the same supplier when it's time to upgrade, than to think about "changing horses in midstream". So Apple installations stay Apple and so forth.
There isn't much doubt that either platform has the computing power to accomplish the task at hand.
As far as WINE goes, I haven't check recently but it was never on the same software "page" with respect to current versions.
Since Adobe software is mostly available in both platforms, that doesn't provide much incentive to move away from the MAC either.
