That’s a big misconception. Latest generation heat pumps can work well even in very cold climates eg Lake Tahoe. The “fixes” needed to make that work aren’t that dramatic eg a bit of pre-heating of some parts with regular electric heating elements.
Your fear of people freezing to death over heat pumps are unfounded. There are backups built in that work with the insulation value of a house. New homes should be very air tight and require less heating, suited for heat pumps.
Even in a house with foam insulation - the highest "normally available" insulation - freezing to death is just a matter of time without heat. When considering city-wide infrastructure it's something that needs to be considered. I'm not saying it's necessarily going to happen, but you'd be dumb not to think about redundancy measures, hence my top-level comment.
This type of redundancy is why many commercial buildings have gas generators, for example.
Heat Pump for heat, Heat Pump water heater is the future for new home builds. Buy a portable generator, a 10kwh gasoline generator is <$1,000 USD and 1/10th the price of a 10kwh batter pack. Problem solved.
They don’t freeze to death.