Mars Bar Syndrome 

Suffered by a product or idea caused by enough people choosing to by or do something different from the perceived norm to avoid being seen as boring or unimaginative. However this causes it to no longer be the norm as nobody chooses it.

Corn Flakes suffer from Mars Bar Syndrome, everyone always gets Crunchy Nut, Weetos, or some other stuff.

Mars Bar Syndrome by Tom Wells May 27, 2008