Also, shipping great stuff requires you to have great hackers to build it, and great hackers have principles. They limit how evil a company can be. You can see this most clearly at Google. If they tried to do anything too evil, they'd face an internal rebellion. Apple employees seem a bit more intimidated by Jobs, but they are pretty idealistic too. A lot would quit if Apple went too far, and Jobs is smart enough about people to know that.
Interesting to see this quote from Jobs during today's Apple earnings call:
"We don't know how to make a $500 computer that's not a piece of junk, and our DNA will not let us ship that. But we can continue to deliver greater and greater value to those customers that we choose to serve. And there's a lot of them."
Almost like he knew we were having this conversation. :)
Speaking of the 80ies, Apple is the one that wanted to control both the OS and the hardware (still true today, from phones to computers), and Apple is the one that sued MS over 'look & feel' issues.
Apple choosing to make their own OSes instead of buy them from an outsider supplier was in those days no different from e.g. building displays or keyboards rather than buying them from suppliers.