>In light of this, I think the deepest explanation is in general economic and cultural factors. Regarding economic factors, it seems that there needs to be a certain level of surplus to support the culture-wide research and development effort that creates inventions.
A related concept is the "adjacent possible" coined by Steven Johnson:
https://www.google.com/search?q="adjacent+possible"+steven+j...
(Linked a google search query because many "adjacent possible" articles are behind a paywall and can't tell which will be visible to you.)