About every part of that description is wrong
.
The only thing I had to do was to move the "aerofly RC 7.app" into the Application folder - and click on it of course...
There's no "coding is more difficult". You either can code or you can't. The only problem is that Windows still has a much bigger user base and RC simulators are niche products which reduces the user base even more.
Also most RC simulators were started to being programmed when OSX was not that widespread. They were not programmed with multiple operating systems in mind, but short-sightedly tightened to one OS.
It's more about companies thinking the required changes to the code base now is more work than it is profitable.