Parking can be very expensive to build. This is a great thread on that. https://www.reddit.com/r/LosAngeles/comments/6lvwh4/im_an_ar...

This is interesting, but it's referring to a very small amount of parking space. Certainly not more than living space.

Parking is a very substantial portion of the space.

" So not only is 32% of your apartment just for your car and otherwise useless, but its also by far the most expensive part of that apartment to build." in the example linked, for reference.

This is irrelevant. Expensive* parking isn't a significant portion. And the amount of space doesn't matter when the space is not limited.