Presh Talwalkar

a best response is a strategy that one player would choose in response to the given strategy profile of another player, or a group of players.

As desirable as this outcome is, it is not sustainable. The reason is that each stand has an incentive to deviate. Either one could choose to locate closer to the center and gain more than half the customers. The other stand would retaliate by moving closer to the center as well, and the game would go on until both end up in the center.

the Bertrand Duopoly. It is characterized by two firms competing solely on price to customers that have no loyalty and simply pick the firm with the lowest price.