That's because you have to pay two sets of people - the Microsoft people who made it initially, and then the company they hire (Aspire, for instance) who has to convert it. Most mac users just aren't demanding games like ZT2. The ones that are are already there - Sims, WoW, stuff like that.
My major uses macs as well; thats why I have both. But you can do all of your adobe stuff on pc or mac, and have it transfer completely with no problems. I do it daily. If that's what you are doing, of course.