OpenGL does not work on all the different distros of Linux out of the box. Some distros do not have sound support at all. Some do not have any input device support, other than a mouse.
A standard UI makes it easier for people to use Linux and go from one version to another. The various distros cannot agree on which version of the X desktop to use.
There are, at least, three different directory structures with as many different installation methods.
Until you can open up all the different distros and use the same installation method for all of them, and they all support the same graphics API (out of the box), and they all support the same sound API, and the same input API, Linux will continue to be an "also-ran" in the operating system world.
People want something that works, out of the box. They do not want to dink around with it. Right now, and for the foreseeable future, putting Aces High II on Linux would be a support nightmare.