Answer:
Median voter theorem
Step-by-step explanation:
The median voter theorem states that "a majority rule voting system will select the outcome most preferred by the median voter".
This means that while there are people that want to go with a certain ice cream vendor, there is a chance that they will actually go to the other vendor because they see more people with the other and this will eventually cause that both vendors have the same amount, or at least an approximate, of customers.