Indeed. However, I'd argue it'd be nearly impossible to have stall-to-stall competition in your standard American city/suburb: people wouldn't be willing to drive to multiple locations, and even if all the vendors were centralized in a market (hmm, perhaps a "super-market" of sorts?), the sales aren't regular enough/in high enough volume to do away with refrigeration, which drives up start-up costs, leading to the classic natural monopoly where the "supermarket" itself is an entity selling the goods.

The Saturday morning farmer's market seems a reasonable approximation of these Chinatown markets at a sustainable scale for smaller/less dense regions. But really, population density is the magic sauce for demand in cases like this.