Western European cities have the enviable advantage of decent weather year-round, just like the US west coast. The central US does not have this; it's more like Moscow: bitterly cold in the winter. And the east coast has a lot of extreme weather too.
Now this doesn't excuse not having good public transit like Tokyo either; it's certainly possible to build that in places like Minneapolis and DC, but they don't (or they simply can't, because the US culturally is unable to).
Cycling is most popular in Northern Europe, which has far worse weather than southern Europe.
And as a cyclist myself, I seriously question how you can claim it to be feasible to bike all winter, in -40 temperatures no less, no matter how you're dressed. I get serious wind-chill problems on my face, head, and hands as soon as the temperature drops below freezing, and that's with a skull-cap covering my ears and some cycling gloves. I do have heavy winter gear I can wear when the weather's cold, but there's no way in hell I can shift the gears on my bike with heavy ski gloves on, and ski pants would probably cause me to wreck. Furthermore, I'm still young enough to not have circulation problems; try telling some 70-year-old to go cycling in -40 temperatures with wind blowing.
It's definitely harder to ride a bike in cold winter weather— but the same is true of walking and driving. One mostly needs cleared roads/paths (as drivers and pedestrians do) and warm, windproof gear (as a pedestrian and skier does). The right bike for city cycling year-round isn't a road bike designed for warm weather high-speed recreation, either.
I wear normal clothes and just add a nice wool 'Buff' scarf for face/neck coverage and good gloves for cycling around NYC in winter weather. I also use snow tires for safety, just because the city doesn't do a great job clearing snow from all the bike lanes, and the bike lane network isn't yet extensive enough that I can avoid mixing with car traffic.
And when it's really cold— even Minnesota closes schools and businesses, anyways: https://www.mprnews.org/story/2015/01/06/school-closure-crit...
So— cycling in cold weather is perfectly possible, and, in any case, most people don't live in places where it regularly gets cold enough for cycling to be truly difficult.