Well, thats not really true. The only reason that the "musician" does not actually get that money is usually because most of their "profit" goes to pay back the record company for advances, equipment, clothes etc...
The more established a musician is, the more they will see. Its hard to make money off one album or your "first" album, because of all the money in advances that you have to take..... and pay back.
I do not want to defend the "music industry", because in general, its slimey. But many people in this debate just do not understand how much money the typical act receives in the form of advances from record lables. Groups such as TLC and the Goo Goo Dolls found this out the hard way. They sold millions, only to find out they owed their record company money.