People are under the impression that things "are just the way they are" in the US, but it is very much a political choice to not dedicate more funding to keeping people on bicycles safe from automobiles.
Transit, for example, can get better with more ridership: more train capacity is added to a line, and more frequent service may occur for better throughput. Both actions would improve service for each individual rider, so while while one may not want it "crowded", having it busy is good. While with roads, an individual driver may want enough traffic so that a street exists, any traffic beyond that would probably only slow you down.
There are also externalities: more walking, cycling, transit reduces pollution and can improve individual health and the collective health of the population. Driving does the opposite.
I'm sure some people do but I know on HN specifically in most threads around american urban cycling you will see some extremely clear-eyed car advocates. They (rightly) recognize that better prioritizing cycling requires, to some extent, fewer resources allocated to car use and oppose it on those grounds.
Some of it is ignorance but a lot of it is not, and a continuing car-centric world is just their well understood and sincerely held value.
Even as a driver, if you think about the second-order effects of getting more (other) people out of their cars, it becomes obvious that it would improve traffic for you. An enlightened self-interested driver would want to increase investment in alternatives to driving, since that is the only proven solution for congestion.
Getting people out of cars also reduces tax spend on road costs. Bike infrastructure lasts longer and is cheaper to maintain than a road, which can result in improved municipal finances.
The thing that is somewhat counterintuitive is that countries with amazing cycling infrastructure are also very good for drivers because you just get less congestion on the roads. There are some great youtube videos about it - how driving across Amsterdam takes less time than covering 3 miles in LA, that kind of thing.
Like, if you like driving cars, a place like the Netherlands is great for it because you spend more time actually driving and not standing in traffic(because most people are out on bikes and not in cars).
In the later chapters of The Power Broker, there are stories of transit advocates and driving advocates begging Robert Moses to preserve right of way for transit when building the Van Wyck Expressway and the Long Island Expressway. The expected traffic demand (~9k cars/hr) the day they opened was far beyond the capacity (1500 cars/hour/lane * 3 lanes). A transit line takes about the same space as one traffic lane, with a capacity of 30-40k/hour. Without provision for transit, the road wouldn't even be a good road for drivers, because everyone with no choice but to drive would overcrowd the road and create the congestion the road was supposed to alleviate.
This is setting aside all other considerations - urban design, air pollution, land and property value, tax revenue, health, neighborhood cohesion, etc. Roads without provision for transit and non-motorized travel don't even do the job of a road well.
Almost every additional cyclist is one less car. And since bicycle infrastructure is a lot cheaper than vehicle infrastructure, spending a dollar on bicycle infrastructure can improve conditions for car drivers more than spending that dollar on car infrastructure.
When I bike and have to wait at a busy crossing alongside other cyclists and cars nearby, I take note of how vastly different the two situations are.
Each car (often an SUV or a pickup truck) typically only has one passenger. Each bike also typically only has one passenger. But in the space of one car at a stoplight, you can fit 3 to 5 cyclists.
People are under the impression that things "are just the way they are" in the US, but it is very much a political choice to not dedicate more funding to keeping people on bicycles safe from automobiles.