It's not really about the size of the country so much as how the infrastructure and cities are put together.

I haven't lived in a household that owned even a single car since the late 90s. We build our work and homes denser and closer together. So for a lot of things I can walk, and for everything else in and near the cities there's busses and trains everywhere.

Basically your culture choose to make you all dependent on commuting in cars. Mostly via the power of letting corporations decide for you.

It's just more profitable for them this way, you have to pay for the cars and the fuel and parking and the roads and the insurance and health care (because cars injure and kill soooo many people). And they profit from all of it. And they use that profit to fund politicians who promote and support it all.