I imagine it's easy, if not expected, for business people to perceive these farmers, plumbers, mechanics, etc. as being unintelligent. Many are slow to speak, and sometimes, when there's a heavy accent, hard to understand. I recall one day standing at my register and thinking about this complex between the overalls and the business suits. While I was standing there, a man came in and told one of my coworkers that he needed an adapter for a goose neck pigtail...this was apparently common jargon for both of them. I thought about all the other people who come in asking for schedule 40 PVC, conduit, solder, elbow couplings, etc. These are everyday requests at our store, but for someone who works in an office in New York, these phrases might not be so common.
Many of these men and women are underestimated. I have found that not only do they excel in their trades, but when asked about things political, scientific, or in some other way academic, they often prove to be very knowledgeable. Sometimes their diction is limited in variety, but the concepts are fully understood. So while a lot of the people I see on a day-to-day basis might not survive Wall Street, I'd wager that not many on Wall Street could find an adapter for a goose neck pigtail if their life depended on it.