The stores alongside it also survive, they all must be in the strategic location to have gotten people passing by that eventually buy some of their products. They wouldn't be able to make it if the stores nearby sells the same products. If besides the fast food stores lies beside a burger king, the two fast food would likely have same problem.
You know actually there is an economy strategy which requires competing companies locate their shops equally in free spaces.
but thats not realistic at all, so there is an opposite one - you collapse all shops in one good place where a lot of people are and they decide where to go by themselves
this strategy works pretty much all around the world and most of the shops are profiting