Why is the issue of GroupThink never discussed in voting?

The 538 tool in another thread prompted me to post something I have been thinking about for a while.

People naturally absorb and adopt their views from their surroundings. Where signals bombard you the most, the affinity will be strongest (and where you are less likely to speak up with a different view). Where signals are less dense, you make up your own mind based on information you go find.

Urban areas have exponentially more influencers on voters than rural areas and it seems intuitively obvious to me that this is what drives the monolithic voting you see in the most densely populated areas.

IMO, the voting divide between rural and urban has much less to do with issues or values and much more with just following the herd.

Probably Germans, but I am just surprised there seems to be very little reporting or discussion about this.