It's funny how outraged right wingers are about this, considering the buffoonery coming from the likes of Glenn Beck on a nightly basis. (Adding .... I don't need lectures on making a mockery of our government from the party who impeached a Democratic president over a blow job. Seriously.)
Colbert is absolutely right, there is no validity to the myth that Americans simply won't do agricultural field work. We've done it before, we'll do it again. But what American's can't do is agricultural field work for $50 a day. And the "free hand of the market" would rather plow fields in Mexico and Chile where the cheap labor is than pay people what their labor is worth in the U.S. So I don't have any answers, because Burger King and McDonald's and the rest have resisted modest wage increases in the interest of corporate profits. In America, we do what the corporations want, not what workers want. Don't see that changing any time soon.
[UPDATE]: And Chuck Todd weighs in:
Yes, if only you were in a position to do something about that.