"by the late 1700s, England had embarked on the largest sustained period of economic growth since the Neolithic age"
Right, and many countries in the world still try to resurrect themselves from that "economic growth" (hint: it was based on pirating their national and human resources). The other "thriving" European countries followed suit (e.g. http://en.wikipedia.org/wiki/Scramble_for_Africa).
After less than six decades since the abolition of explicit colonialism, it's still quite early to say why some countries recovered quickly while others didn't.
While I'm a great believer in democracy, I think we should be aware that a lot of these approaches are nothing but self serving democratic propaganda (propaganda, not science).