Anyone who thinks Gates is both a genius (as in programming genius) and that this genius was responsible for the success of the company is wrong. One of those is not a true statement.
Gates and Ballmer were very aggressive and sociopathic, like Steve Jobs. This helped the company succeed. But success is really the result of the young talented programmers who signed on with them, and worshipped these characters.
In MS's case it was Simonyi, the man who gave us Excel. And before him, it was Allen who helped Gates get into business. Gates could not write the compiler tools himself. He needed Allen.
Some people might not appreciate the way these guys treat employees. Many simply would not tolerate being belittled by a guy who is not as smart as they are. (Gates' famous line "I don't know how technical your are." was supposedly his way of dealing with the many, many others who knew more than he did.) But... many programmers are happy to be treated this way. And this is management formula that works very well. Belittling the young and easily influenced, especially software programmers, works. Perhaps that is Gates' and Jobs' genius.
Read Cringley. I think you will come away realizing guys like Simonyi were the true geniuses.
Hollywood ending to this comment i.e., the moral question leaft to the viewer/reader: Not all geniuses are good leaders, but is it necessary to be an a-hole to be an effective leader (of geniuses)?