Besides, if it was not how would it have lasted 40 years?
Unix is evolutionary superior, not technically superior.
It's like the free market. Cheap products of low quality takes out competitors of higher quality, because they are more expensive. Unix is overly simplistic (aka low quality), as a consequence it's portable (aka cheap). The result is, it's evolutionary superior.
Compare scheduling algorithms: In Ubuntu 10.04 beta, if I play music in the background, it stops for several seconds at a time when I installing updates or if for any other reason the computer is under load.
And I've had similar problems with OpenBSD on another computer.
I've got a 2+ Ghz computer and it can't play music as my 133 Mhz Windows 95 machine. It's ridiculous. Grow up unix fanboys.