In Catastrophe by Munshi Premchand, a woman owned a parching oven. Apparently, business was quite good: "The village folk have one meal a day of parched grain, so there was always a crowd around Bhungi's oven." However, it also says that "she didn't own either a scrap of land or a house to live in. Her only source of livelihood was a parching oven." It further says that "she lived in Pandit's village" and that Pandit had the ability to compel her to parch grain for him for free, in which case she would go to bed hungry that day (because her paying customers would normally give her part of the parched grain as part of the fee for parching their grain, which she would then eat - the implication being that, without that source of food, she wouldn't have any food).
That being said, given the fact that she was the village's sole provider of an in-demand good, why was she apparently so poor?