Do you think these rich blue cities will just sit in their cold apartments and wither away(well, most will)
No, they will organize their armies and seize the energy supply (Nuclear, hydro, gas etc and expensive whatever lives it takes to secure and maintain that supply.
Millions will die in these areas but millions more will die in the suburbs and rural areas where electricity will be cut off and food denied because of transportation and production interruption.
Think the blue areas will allow food to be killed and packaged? Think again
Most wouldn’t know how to turn wheat or corn into flour and cattle herds don’t jump into the meat grinder by themselves!
Herds would be decimated by the nearest blue areas anyway. At a cost,sure but urbanites have lots of surplus mouths to eliminate anyway.
It will be a bloody mess and then we die.
What armies?
The gangs? The ones that throw around hundreds of bullets to kill one kid three blocks over who was not involved in their dispute?
The police who, sadly have pretty much the same problem?
And where are their supplies coming from?
Who are they going to get to run the power?