Why was the printing press a success?

The press, or movable-type, allowed books and in turn knowledge to be mass produced. Little is more valueble and marketable than knowledge. Before the press, all works and communications were copied by hand at VERY high cost and at an excrutiatingly slow production speed. Movable type changed that over night. Also, before the press, only elites could afford books, so only THEY had a reason to learn to read or even want to. Suddenly the Upper-middle-class on down to the paupers had reason to learn to read worldwide and was in turn a major precursor to the Enlightenment, Renaissance and democracy.