"Mr. Mercer, a college dropout, joined Apple in 1987. While there, he was the lead designer of Version 7 of the Macintosh finder, the operating system’s graphical desktop. He later founded Pixo, a software tools firm that created a development system used by Apple software designers to conceive the first version of the user interface for the iPod music player.
More recently, as an independent designer, he worked under contract with Samsung to design the Z5, an MP3 player that has been a best seller in South Korea."
No one can deny that some person is really bright and as a result successful.
It's possible for bright people to fail, but to label all successful people "not bright" is silly.