It was actually the development of cheap paper that propelled the use of Gutenberg's movable type. So long as either writing or printing was done on very expensive parchment and vellum made from animal hides, there was not much economic advantage from movable type because print runs on a very expensive medium would be short. The cost of materials dominated the labor costs.

About 1350 the price of paper began to fall exponentially in England and Holland. This made movable type economic almost 100 years later.

See Figure 5 on page 10 of "Prices and the Growth of the European Knowledge Economy, 1200-2007" https://www.diva-portal.org/smash/get/diva2:384596/FULLTEXT0...

The Moore's Law of paper prices was to printing as the Moore's Law of silicon integrated circuits is to the internet.