Those can be warmed up with a g̶a̶s̶o̶l̶i̶n̶e blowtorch. Or you can fit your car with an alarm system that auto starts the engine throughout the night to keep it warm. That's what pretty much everyone is doing where I'm from (-25°C is a pretty typical winter temperature here, with drops down to -40-45°C for a couple weeks each winter).
After that you get tolerable gas mileage. I don't drive much, but from my friends' description it sounds like you get around 30-40% more gas usage compared to warmer months.
Maybe in Norway or Canada or other 'rich' countries.
Most people have no place to park their cars, they just leave them wherever in the open (since most live in apartments and there are few garages available).
Those who have enough money to afford an alarm system and pay the increased gasoline bill (because it adds about an hour of idling your engine each day) rarely revert to such measures, but many do. I see them every morning when temperature drops below -30°C or so.
It's pretty dangerous, burns down quite a few cars each year, but people don't care or have no other options. I think during the last couple of years there were two fires near my house alone.
After that you get tolerable gas mileage. I don't drive much, but from my friends' description it sounds like you get around 30-40% more gas usage compared to warmer months.