Regarding exogenous technological change, it occured to me that I didn't
really know who Gutenberg was, nor whether he fit the profile.
I'm quoting a bio of him in full, because it doesn't have a copyright on it and I can't figure out where it came from originally, other than by the style of writing it is probably 19th century or earlier and probably a translation of a German original, and thus likely long out of copyright:
GUTENBERG, JOHANNES, or Henne, who is regarded as the inventor of the art of employing movable types in printing, was born near the close of the 14th century, at Mainz. He was sprung from a patrician family, which took the name of Gutenberg, or Gensfleisch, from two estates in its Possession. Of Gutenberg's early life no particulars are known, but it seems probable that he devoted himself at an early age to mechanical arts.For "patrician family" then read "middle-class" now. He was apparently a tinker, who might have been tuning cars in the 1950s or computers in the late 20th century or early 21st.
