"Generally speaking, people are much too fast to try to explain [...] things in terms of cultural differences."

This is an important point I might have underlined if I'd written the post today. I think it applies to a lot of stuff besides the desired mode of transport problem.

My main point in this context would probably be that if you want to compare political- or societal structures and decisions - which many people seem to want to do even though it's very hard - you need to know a lot of stuff. Additional information makes it harder to maintain a faulty model.

Incidentally on a related note I may be wrong, but I have the impression that a lot of people living in developed societies tend to assume that environmental constraints are often things that we can just work our way around, that they're just engineering problems, and so are often not important in the big scheme of things. I.e. 'developed societies are past those problems, and being past those problems is part of what makes a society developed', rather than developing. I think that's a potentially very problematic way to think about these things, and I think that that line of thinking may make you overlook important stuff.

My understanding is the milder climates in Europe are caused by there being an ocean to the west of it - the western United States gets the same sort of temperatures. There's probably more to it than just that, but in general, west coasts in the Northern hemisphere get less temperature variation than east coasts and inland areas.

As to the walkable cities - that's actually General Motors' fault. A lot of cities had good trolley systems in the 30s, but they were privatized bought by companies with ties to the auto industry, which then replaced them with buses. People didn't like the buses, so the bus system gradually died back as people bought cars instead. I suspect culture is also part of it - Americans really like to be independent and self-sufficient, or at least feel like they are. I'm told that fits well with having a car, for a lot of people. (I'm not a very good driver, so I feel more independent when I can get where I need to go without driving, but each to their own.)

If climate also contributes, then I'd expect west coast American cities to be more walkable than east coast and inland cities. It might be most useful to make the comparison based on the 50s, 60s or 70s, once cars were widely available, but global warming was not considered a major issue. (Western cities probably also tend to favor walking because people there are more liberal, and so would want walkable and bikable cities partly for political reasons.)