[ben_w]

I don't understand your example for the second kind. Even with your own words, "Einstein, who was able to devise new theories based on existing knowledge", that sounds to me much the same as the first kind, because of e.g. GR coming from Riemann geometry, and SR coming from Lorentz transformations.

Looking back at history, it's kinda remarkable that the ancient Greeks, who knew the surface of the Earth was curved, didn't realise this curvature itself was a contradiction of Euclid's triangle angle sum. Likewise, should it be difficult to invent discrete spaces, once someone has asked if atoms exist? Evidentially both were difficult, as the gap was thousands of years.