Assume /u/onion2k was referring to the US, many countries successfully push public transport more than the US. So human nature certainly isn't the blocker here, but the current culture of the US.
But within individual cities, or areas like the Northeast Corridor, the density is comparable to areas of Europe with fantastic public transit.
The issue is car-centric policy and culture, not lack of potential demand.
The absolute size of the land is irrelevant; the only thing that matters is how far people actually travel. If your state is 1000 miles across, but most of the people stay within 5 miles of their home most of the time then public transport is completely viable. People who want to travel further can still own a car, or just rent on when they need to travel a long way.
While good public transport isn't an option everyone will continue to own cars, and while people own cars public transport will be under-utilized and expensive. It's a chicken and egg problem.
> Because of that scale difference, it is hard for public transportation in the US to appeal to our innate desire for convenience.
I don't really understand what you mean by this. Public transportation is extremely convenient. I love driving (I grew up in California), but find public transportation in Sweden much more convenient than having a car.
Honestly I'm having trouble understanding the core of your argument.
> Most of those other countries are like a small US state, but the US is much, much larger. Even a medium sized US state is larger than most of those countries. There is a massive scale difference that needs to be taken into account.
So I was really kind of giving the benefit of the doubt when considering population density.
That said I understand your point. But that doesn't explain why US _cities_ put so little effort into public transportation. Even ignoring the dispersal across the country, the US seems to not care to handle the problem on the local level where it really has no excuse at all.
As to your comparison with population weighted density, here are comparisons between the US and Sweden:
* "While the overall U.S. density stood at 87 people per square mile, population-weighted density shows that people actually lived at an average of 5,369 people per square mile."
https://www.smartcitiesdive.com/ex/sustainablecitiescollecti...
* "Population-Weighted Density for Sweden was found to be much higher compared to simple density, 2288.8 people per square kilometre instead of 24.0 for 2015."
http://www.diva-portal.org/smash/record.jsf?pid=diva2%3A1081...
So it looks like the population weight density of Sweden would be 2288.8 * 1.609 * 1.609 = 5925.4308328 per square mile which is apparently 10% higher than the US.
Now honestly that doesn't really seem to explain the difference to me. Is 10% such a big difference? Besides if it is, Sweden wasn't always at this value. In the past few decades, people have moved into cities so what I really wonder is how far back do you need to go historically before Sweden was lower than the US current number? As in, at what point recently was Sweden in a worse position? Personally I think the best explanation for the US' current position overall is cultural: they really just don't want to give up their cars.
Anyway thanks for the info. Looks like I'd personally need to put more time and research into this than I have available, but I'll try to keep this info in mind going forward.