That's kind of a narrow take; the mainstream may be directed towards a good thing and just not have the depth to draw a benefit, its attention being superficial and fleeting.

E.g. the Pavlovian dog metaphor is quite a mainstream trope, but doesn't it carry an important message nevertheless?

If anything, I would say that fleeting takes and offhand dismissals are what determines and solidifies the mainstream's superficiality.

My whole comment refers to the "Propaganda" book by Edward Bernays.