But then, through the turmoils of the late 1400s and 1500s, England had become a land of immigration. We often think of our America as being that place to which persecuted people fled, but it was England first ~ which was, at the time, a fairly decent place to live compared to most other places.
yes, french, germans, spaniards etc. But I disagree with your last point -- England was climatically and culturally lower than mainland europe, especially the lowlands of Belgium-Holland-Luxembourg and Italy etc., but it was safer from strife as you point out.
Regarding Cornwall, the 1400/1500 period in Brittany reveals agitation to avoid absorption by France, and even to join Spain. Given the close cultural and linguistic affinities of the two places (which had really only be one as far as economics were concerned as late as the 1300s) the English nobles probably had good reason to start hanging Cornishmen left and right ~ which they did in huge numbers! The lists of Cornishmen executed by the Brits was one of the first large data bases posted on the Internet. Haven't looked it up in a while, but doggone!