That’s definitely a big part, but it’s both. Like white flight out of cities and insisting on a detached suburban home, the other part of the story is that cars represent “social worth” for many in North America.
It’s why car people become so angrily defensive, and fight even modest changes. Cars aren’t just functional. They represent a cherished value system. Their worth as a person is tied up with their car.
That said, just like diamond rings and smoking, even this weird cultural norm was bought by industry advertising. We’re social apes, who do things to feel important and valued, even when it otherwise makes no sense.
I also think most people haven’t tried and would be pleasantly surprised if they did. Even in the US, almost half of all trips are bikable or walkable distances. It doesn’t have to replace your main commute, just some of your trips.
We’ve all met those people who get in their car to drive two blocks instead of walking, even in good weather. Cars are so dominant that there’s a lack of imagination around using anything except cars.