Here are my 2 cents. The competitive pressure requires most of the effort to be targeted in improving the product on the mainstay platform. If a company with limited resources (which all of the RC sim companies are) assigns developing time in porting the product to another platform, the mainline product will not be updated/improved because developers have been re-assigned. Product that are not constantly improved fall behind and the sales will drop and dry out. The company will be left with obsolete product and two code bases to support or modernize with no revenue stream.

Stefan
http://rcflightsim.com