Re: more buy in
Linux was the first x86 Unix that supported my hardware. That's really all there is to it.
You can make all of the excuses you like but I think the fact that Linux was a populist Unix early on contributed to it's popularity quite a bit. At the time, I would have been willing to shell out the coin necessary for Solaris x86 or OpenStep if only either of those actually supported MY hardware.
On a long trajectory, a very small angular deviation can account for a very big difference where you end up.