Gutenberg solved an incredibly complex problem. He figured out how to produce 300 copies of a book for roughly the cost of one book. That is not a small improvement. That is a restructuring of the economics of knowledge.
And so what does he do? He prints Bibles. However, he has 300 Bibles sitting in a room in Mainz. Then he discovers that he has an abundance, an overcapacity. In the landlocked German town where he lived, only a handful of people were legally permitted to read the Bible. Gutenberg's creation leads to his bankruptcy.
Then comes Johann Fust, a creditor who seizes the press. He decides to go into the printing business himself, since he now owns the equipment. He goes bankrupt too. Then Gutenberg's apprentices scatter across Europe and build their own presses. They go bankrupt. Build a printing press and go bankrupt, the same story over and over for decades.
"Remarkably, great innovation seems to begin with the bankruptcy of the innovators. It took 40 years before a printer anywhere in Europe could reliably make any money."