Monoculture
Appearance
Applied to crops or vegetation, a 'monoculture is an environment with no genetic differentiation between members of the population. Monocultures are almost universally agreed to be undesirable because of susceptibility to disease and insects.
A monoculture can also be any sort of system wherein everyone is wearing/doing/seeing/reading/watching/thinking the same thing.
This article needs to be expanded beyond a dictionary entry.