[gen220]

Just spitballing, but I imagine it was probably influenced to a lack of demand, in addition to the difficulty of building new technology. There was a large demand for standardized coinage. Not a large demand for cheap books. Near-universal literacy is a recent phenomenon. It used to be that literacy required a literary-based education, and a literary-based education required wealth or institutional support.

If you were wealthy, you could afford to purchase books that were the result of expensive bookmaking processes, or if you were an institution (monastery, government), you could hire people to copy texts by hand. Why bother with cumbersome new technology, when money is cheap and the means are at hand?