What the page you refer to discusses for the Mac isn't FMS. It's a dead link that redirects to a page no longer lists the heli simulator.

There isn't a version of FMS for the Mac.

What strikes me in all this is the amount of competition in the PC RC simulator business. There are what, 3-4 commercial products, plus FMS? Where does a new product such as FS One expect their sales to come from? That market isn't full of people anxious to buy yet another RC sim. Of the Windows RC'ers likely to purchase a sim, how many of them already have done so? Are the commercial sims just trying to cannibalize each others' market share? Where's the growth going to come from?

My guess is that nobody has ever done a market analysis here.