It is very difficult, in fact almost impossible, for individual farmers to beat supermarket prices any more, largely thanks to vertical integration within agriculture and food processing.

This means that by and large, the point of farmers markets now has to be mostly about what you declaim: "bourgeois bohème type". If you don't have much money to spend on food, you won't be buying it directly from farmers anymore. That's sad, and seems weirdly wrong, but that's one of the paradoxes of scale in an industrialized, fossil-fuel enhanced agricultural system.