People who live in big cities where apartments of 344 square feet are normal don't waste massive amounts of space on parking for cars -- there will be stores within walking distance, and they probably take the subway to work.
If the guy lives by himself, 344 ft^2 really isn't small at all. My wife and I share just under 38 m^2 (408 ft^2) and, while not spacious, our apartment certainly isn't tiny. We have a kitchen, living room, and bedroom, plus a bathroom, and a balcony on which to hang the laundry. This is in Tokyo, where density is about the same as Hong Kong.
When we have a kid, then we'll start to feel cramped. But there are other people in our building raising kids in rooms the size of ours!