Two sides are forming and neither are very nice.
Agreed. Both sides of the establishment set this right-wing populist wave up for themselves a while ago. Democrats have become more entrenched in identity politics than economics and Republicans have become too concerned with furthering their own political careers.
Now, both the left and right have become reactionary groups of individuals who can't stop bickering over each other's policies.
Though I think in Brexit's case Remain people were less motivated to vote than Leave voters.