Some more info about Gentle Giant - the band was started by the British Shulman brothers. One of them, the vocalist Derek, became a famous record company executive after GG broke up. He was responsible for signing many famous artists.
http://en.wikipedia.org/wiki/Derek_Shulman
Its a bit of irony that he became rich and famous for foisting Debby Gibson and other pop artists on the public, but Gentle Giant was never able to turn the corner of commercial success.
BTW - for many, it was Derek's voice that prevented the band from achieving that commercial success. I believe that might be true. Its similar to Les Claypool of Primus - the music overcomes a vocalist whose voice is destinctive and loved by devoted fans, but is also a major obstacle for mainstream success.