> The argument in the paper is that it's not just a mild inconvenience, but rather a complete showstopper for many couples, that they can't afford a larger car

> The argument in the paper is that it's not just a mild inconvenience, but rather a complete showstopper for many couples, that they can't afford a larger car so they simply stop having children. If they cannot afford a larger car now, they most probably cannot afford the cost of raising a third child in the coming years, so that they are dissuaded immediately instead of being into deep financial trouble down the road is a pretty good outcome!