The skiffle movement only predated the Greenwich Village folk revival if we ignore the latter until its third wave. The Village was the center of what as far as I know was the first fairly large-scale attempt of urban Americans to play the music of rural Americans--what we normally mean by a folk revival--starting in the late 1930s. The UK got this directly from Greenwich Village, thanks--if I'm recalling correctly--to a BBC broadcast of Josh White and Lead Belly at the Village Vanguard in the early 1940s. If there had not been a Village scene nurturing Lead Belly, Lonnie Donegan would likely never have heard "Rock Island Line" in the first place.

That is not to deny the influence of Donegan's hit in the US--I assume that Snooks Eaglin's version of "Rock Island Line" was based on Donegan's, and there was certainly a lot of give-and-take between the UK and US scenes. But the Village was firmly established as the center of US folk revivalism by the mid 1940s, thanks to the Almanac Singers, Josh White, Burl Ives, Richard Dyer-Bennett, Susan Reed, and others, who were by far the best known "folksingers" of that period and all of whom except the Almanacs made their names at the Vanguard and Cafe Society, specifically because the Village audience was into folksongs, along with jazz.