Alright, let me rephrase. I don't know why they bothered to KEEP updating UNIX after windows was released. The fact that UNIX was released before windows and is STILL hardly used just proves my point. lol, and apparently in the eyes of most beholders, UNIX doesn't qualify as being "user friendly".
windows doesn't run on mainframes, unix can be compiled to run on almost anything, and that is where unix came from, originally it was made for mainframes, and to this day it still runs on many of them, hardly used? its very popular in the business world, even these days
linux on the other hand started as a free version of unix made to run on desktop computers, and nowadays linux runs on pretty much any architecture made including some mainframes
and evidently Apple computer inc felt it was good enough to use it as base for OS X by using freebsd4.4(about as close to unix as you can get without paying for it), and OS X is very user friendly yet retains all the traits of a POSIX compliant OS
it can be as user friendly as you want to make it