[ryanhuff]

Sure there are barriers. A few that come to mind include the $99 per year Apple developer program fee, which is necessary to distribute apps, the Mac OS requirement, and the objective c hurdle. These may seem more like inconvenience barriers, but they do keep people away from the development pool.

[steve-howard]

I'm sure as hell not buying a Mac just to write for Apple's walled gardens. Inconvenience is an understatement.

[ryanhuff]

While not ideal, some people have been able to run mac os on other operating systems using virtualization.