Some more context as someone living in Korea right now, "cheap" cars in Korea are quite rare, especially in Seoul. Having a car is somewhat of a luxury and not needed for daily life. So I think this is trying to move some of the cost of clean energy towards those who can afford it.
I wouldn't call it luxury. It's just that people don't find it attractive while living in Seoul. Average joe definitely can afford having a car.
"An advanced city is not one where even the poor use cars, but rather one where even the rich use public transport."

> Having a car is somewhat of a luxury

That's true in many other places, too, like many European and US coastal cities where car ownership rates aren't nearly as high as many people probably think they are.