Weather ?
Say it's raining, this makes riding a bike much more dangerous. Or even just heat, if it's over 90 F out biking is going to be rough.
American cities are spread out to the point you may need to drive 5 miles to buy some oat meal. Fix that first, I'd vastly prefer smaller cities.
"But what about people who can't cycle?" - Most people can cycle. Besides, what about people who can't drive cars? Why do we invest in extensive car infrastructure when some people can't drive cars, either?
"But what about the weather?" - Some people in my city don't like cycling on a rainy day, so they take a bus or drive that day. Tomorrow, when it's not raining, they'll cycle. This still results in less cars and more cyclists. Most of us don't live in perpetual rain or snow. Not to mention the fact that plenty of people don't seem to mind cycling in the rain or snow at all, so they utilize the cycling infrastructure year-round. "Sometimes the weather is bad" is not an excuse for avoiding bike infrastructure, in my opinion.
I agree on cities should be laid out in a way that encourages and enables cycling. I think building safe cycling infrastructure, such as dedicated paths for cyclists (separated from cars) is a good start.
I don't think most Americans are fit enough to cycle , that's ultimately the issue. But even if your overweight, taking a train isn't a problem.
My point is not that all Americans should suddenly start cycling everywhere at all times. That's unrealistic and undesirable. I get the impression that you're viewing this as some kind of all-or-nothing thing, where as soon as you build a bike path people will be forced to exclusively cycle and not walk, or drive, or use public transport.
My point is simply that building cycling infrastructure that would support people who'd like to cycle some or all of the time is a good thing. Me not wanting to cycle in snow doesn't mean my neighbor doesn't want to cycle in snow, and luckily he and others like him (of which there seem to be plenty) have a bike path to do so safely and easily.
I think it's relatively safe to say if people weren't worried about getting hit by a car, or falling into a pothole, or crashing into a pedestrian, or getting yelled at for being on the road, _more_ of them would choose to use a bike and experience the benefits of cycling.
As a sidenote, I'd also like to point out that you don't have to be super fit to cycle, although cycling can certainly help improve fitness over time. There are bikes built for a more relaxed ride, as well as bikes with electric assist. It is possible to pedal as fast as you want, and go for whatever distances one is comfortable with.
At the same time, unless you radically redesigned American cities, cycling commuting won't work. City layouts take decades to change, even if people want change. I don't see a push for more compact cities in America ( luckily this is just one country, I already have work auth for at least 1 other place).
I plan on getting a cheap Fixie bike next, I had an insane amount of fun with a 100$ Big Lots bike a few years back.
I also know several people who have various form of physical disability who cycle either totally normal bikes or ebikes, or adjusted (to different degrees) bikes or ebikes.
If we had better cycle infrastructure where I live (a relatively small European city), many many more people would release that they can get where they're going faster and cheaper on a bike than in a car, and have more fun while doing it. Even when it's raining.
Wait what, why? Because I'm going to get a bit wet? The rain is no more a threat to a cyclist's safety than it is to a car on a wet day. You just might need to wear a rain jacket, too.
The Dutch certainly don't give a shit about rain, snow or shine, as the saying goes "there's no such thing as bad weather, only bad clothes."
If you have a city of Lance Armstrongs , sure everyone could bike commute. That's not practical though.
I'd argue for building more bike infrastructure just since cycling is fun. I'm planing on working remote forever anyway, so I think we'd agree on alot. But I recognize my privilege here, if you need to commute to an office biking won't work over a few miles.
The average American is commuting 16 miles each way. Can you realistically do this on a bike , I know I can't.
https://itstillruns.com/far-americans-drive-work-average-744...
In areas with frequent rain, people are practiced in carrying waterproof overclothes and such. Sub-zero temperatures, snow and ice can be a much bigger problem, of course, but good maintenance resolves a lot of that, too, as it does for cars.
As noted by drakonka, you continue to argue the infeasibility of something that works well for many cities/countries, citing things that those with experience know aren't a big problem. Sure, you can't just suddenly start cycling when your life/city is built around driving tens of miles, but a city/country can work towards biking in a way that has worked well around the world.
I'm afraid braking won't work as well, and I'll end up hurting myself.
I don't think inexperienced drivers should drive in the snow, but that doesn't mean we completely dismiss cars as a practical means of transportations in cities that get snow.
Before covid, when I commuted, I used to cycle in 11 miles each way every day. Except when the temperature dropped below 5c. Not because I didn't have warm clothes, but because once I hit some ice under a bridge travelling at ~20mph and came off. It took a long time for the wound on my knee to heel from that.