True but I don't think stalls are that significant part of income for the company. Moreover, it's not good to always think about the money first but to see past that and realize these kind of features improve the gameplay making it more convenient and just better for the consumers. And that can lead to increased income for them. After all, lots of people including myself have many different items to sell and purchase at the same time so I would definitely need to buy the stalls even with this system.