> The US has bigger families
I'm not making fun of big SUV cars in the US, but about the big normal cars. For example, taxis in NY are huge, but they carry exactly as many people as a smaller European car.
Many places that historically had town cars and carriages seem to kept large cabin taxis because it was more attractive to people to ride in comfort (not having to crouch to get in for example) as well as allow you to easily pick 3 passengers with enough room that they don't have to be touching.
You also forget that more than 50% of NYC's taxi's are hybrid these days, with the Prius being one of the most popular models to be converted. https://en.wikipedia.org/wiki/Hybrid_taxi
It's hard to have a second kid when you live in an apartment and drive a Fiesta, and it's really hard to justify a third. A fourth? Forget it.
But considering that even countries like Iceland that do culturally were having big families, and living in big houses including split houses where the parents and grand-parents live in connected houses also is suffering from a similar fate I might not be as simple as that.
I would say it's a "natural" development of of current life styles, the US managed to delay it maybe because for a long long time and especially after the war the concept of the American dream, a big house, a hot housewife, and 3 kids was in full gear.
Now with the American Dream being less relevant, and much less attainable to many Americans we see a switch to less children, less marriages, and more adults living alone.
Compare to 1.4 in Italy (and I thought they were Catholics!) or 1.38 in Germany.
Actually now I look it up the US is only 1.88 in the last stats that come up, so Iceland is out-breeding the US.
Edit: and while I don't know why I bother researching and typing these things since I inevitably wind up with negative karma the moment I suggest something not directly in line with HN herd opinion, I wish to add that the top-selling car in Iceland is the respectably mid sized Skoda Octavia.
And it's also quite a sharp decline since the 80's and 70's for Iceland, just like for any other Western country.
The US has bigger families, the UK has currently the biggest family size at slightly over 2.4 and more 3/4 kid families than all of mainland Europe combined due to immigration.
Most households in the EU do not have children, only 21% of the households in the EU with 2 adults have children (31% of all total households have children, in the US even tho the number have dropped in half in some sectors since the 70's it's still 47% of all households), and that number drops to single digits for households with 1 or 3 or more adults.
The US driving distances are also quite larger, while you can drive from France to Germany most people do not, in the US driving 100's and even 1000's of miles isn't unheard off, and it's not unheard off having to drive 50 miles or more to get to work in each direction these days.
And while it's true that the SUV isn't that popular, the station wagon is pretty much the SUV of Europe, I've never seen Audi S3 SWG's and i didn't thought any one would even make those until I spent some time in the Netherlands and then seen pretty much every car model in SWG form including sporterized models like the S3/S5 which i never though anyone would ever want to make yet alone buy.
But in general if Europe would fuck a bit more, and actually have kids and not sustain it's population growth entirely through immigration (because "native" EU population has been shrinking rapidly since the 80's with 1.2-1.9 population growth factors which are below sustainability) SUV's and minivan's would've been much more popular here too.