OS: the huge pile of code that you need to get process abstraction, a file system, networking and possibly some human interface stuff up and running. Code best not seen nor heard because that means you're not doing what you should be doing: using applications or writing them. OS software is a commodity, and with portability being Linux' mainstay it can now be found on processors of almost any pedigree. Linux is all a…
It's not the proliferation of choices that's the problem, its that so many of those choices don't work.
Linux doesn't have too many problems with multiple choices. Historically I've seen a couple situations where multiple kernel drivers target the same hardware, but this usually shakes out pretty quickly. Arguably some of the weirder filesystems shipped with the kernel have not quite been enterprise grade. But overall the kernel has high standards.
Coincidentally Debian just released another stable last weekend and the short version is if the maintainer(s) package doesn't play well with others, the package gets yanked (via a release critical bug, which means either you fix it soon or the package gets removed from the release). So either it cooperates with the rest of the system, or its not part of the system anymore.