Today it is extremely common for someone in the "blue tribe" to know no one who is in the "red tribe" - people who (to use a few stereotypes) are Christian, enjoy NASCAR, and unabashedly eat at chain restaurants. People in either tribe don't encounter each other daily and as a result both tribes have little understanding of each other's worlds or the number of people who are not in their tribe.
Inequality is deeply problematic and there are no easy solutions. Liberalism recognizes this. The problem is that the tribal line now runs along an economic fault line. Red tribe hasn't been doing well - red states are full of disadvantaged people. Worse, because of identity politics they have been made "the other" and rendered relatively voiceless.
Liberalism can champion the disadvantaged but it has to approach them with solutions. As technological displacement of workers continues it is hard to see what they will be.
I am blue tribe but I flinch when I see my colleagues in the tech industry complain about things like the injustice of having to go to a whiteboard in an interview to get a job in a Crèche-like work environment with play-balls while people outside the industry are lucky to get jobs driving cars, cleaning tables, or lifting boxes without health insurance. We don't see our own sense of entitlement. It is transparent to others despite our liberal signaling. This isn't going to be a pretty ride.