You can idle a ICE car for maybe 16 hours easily with a half-tank, although this varies a lot [1]. With rationing your fuel, running for 10-30 minutes for every hour, you can maintain survivable temperature for at least double that (32 hours on half tank) to perhaps 96 hours, or 4 days. Double that for a full tank of gas.

If you want EVs to take over, get feature parity with the current technology.

[1] https://www.autotrader.ca/editorial/20190201/how-long-can-yo...