In fact, it seems that anyone who has some exposure to ranching, knowledge of the vocabulary, and some understanding of humor is welcomed. Though it is true that you can only write what you know, there are many ways to know something. It is also meant to be read aloud, memorized and recited. It is a performance. The main differences exist, not so much in subject, but in presentation and audience.
Today there is a strong public performance movement.
You might well see cowboy poets at county fairs and cattlemen's dinners. Also, the audience today is as likely to include plumbers and professors as it is poets and ranch hands.