Sure, it works in your context, you live in a city with 9 million people and you sometimes rent a car - fine. I live in a city 100x smaller. I literally don't know a person that doesn't own a car, or at least has access to a car.
The context actually get far more granular than it. I lived without a car for 25 years of my life, buses and trains were enough. But all it takes to require a car is having a home 3-4 km from the city center bus stops (which probably covers >50% of population). Unless someone likes walking 1h one way in -10 deg in winter to get to work each day.
A city 100x smaller is a city with 90k population. That's half of the population of the Upper West Side. And the UWS has an area of only 5 square kilometers. Unless you specifically choose to, you are not going to walk 3-4 km.
-10deg winters are certainly going to put a stop to much walking or biking, regardless of whether that's Celsius or Fahrenheit.
Not much of Europe ever gets that low though. Edinburgh occasionally overnight, but it's rarely below about -4c / 24f during commute hours. Berlin mostly the same, Stockholm's maybe the only big European capital that gets to "walking for an hour stands a serious chance of killing you" temperatures for days at a time.
The context actually get far more granular than it. I lived without a car for 25 years of my life, buses and trains were enough. But all it takes to require a car is having a home 3-4 km from the city center bus stops (which probably covers >50% of population). Unless someone likes walking 1h one way in -10 deg in winter to get to work each day.