But the difference is that because Linux is open source, which allows it to be worked on by a large collaborative set of developers, it has also been built to be platform agnostic. It's got what we call horizontal layering of function, so you can easily port the OS to multiple machine architectures and platforms. In other words, Linux, even if it may have started out as a hack to run Unix on a cheap Intel processor, has since evolved into the ultimate protean operating system. Over the years, its functions have been streamlined and compartmentalized to the point where it has become relatively easy to adapt it to different systems. His argument was that simple systems that get most of the job done are better at surviving, over the long run, than complex systems designed to do everything perfectly.
Complex systems are hard to adapt to new situations, and can break down easily.
Simple systems can be fixed quickly, and mutate even faster. Linux is just the newest all-purpose building material. Which in turn makes Linux-based systems even more attractive. And that's the business case for open source.