Simplicity is far from being an essential part of folk music. Listen to some Macedomian dances, which by any conceivable standard qualify as folk music, and the rhyhmic complexity betokens a highly sophisticated musical cultire.

As for the songs, many of the traditional songs performed by, say, Martin Carthy, or June Tabor are hugely complex both lyrically and rhythmically.

I am of course, talking about "real" folk music here.

Murray