Precisely that- a myth. History claims that the working class of Europe came over to the Americas that were empty and wild and built an entire country out of the ashes, when in reality most settlers that originally came here were petit bourgeois seeking to become bourgeois themselves as the contradictions of capitalism were piling up in Europe and causing more and more people to be wage slaves, which apparently was a fate worse than death to them.

All of this is in Settlers so do yourself a favor and read it