Lack of writing was the problem (and paper). The most effective innovation was the printing press - what followed was an explosion of technological progress.
The movable type and printing press combination was introduced by Gutenberg in 1455 and in a single generation spread to hundreds of European cities. By 1500, there were 20 million printed books in Europe for a population of 70 million, mostly illiterate.
It was a cultural revolution, in half a century the price of books dropped by an order or two of magnitude. They were transformed from a luxury item only the wealthiest could afford to something any middle class, literate citizen could own.
Interestingly, in Korea, they had movable metal type some decades earlier (in 1377). Check out the image and text about Jikji, "from Korea, the earliest known book printed with movable metal type, 1377" (from the Wikipedia article about Printing) at the bottom of this blog post:
Cunei form also had moveable type. Afaik most was still handwritten though.
There are hundreds of thousands yet untranslated cunei form tablets in museums and maybe many more that never made it through time.
From "Moveable type" wikipedia:
"Seals and stamps may have been precursors to movable type. The uneven spacing of the impressions on brick stamps found in the Mesopotamian cities of Uruk and Larsa, dating from the 2nd millennium BC, has been conjectured by some archaeologists as evidence that the stamps were made using movable type."
