As someone who’s adopting bikes for most of my utility needs, food shopping, dropping kids off at school, one thing I can’t agree with is that cars are more convenient. In general, I find cars to be far less convenient. They are annoying to park, often get stuck in traffic, and generally are just annoying large boxes that you need a lot of space to maneuver. Using a cargo bike for most of those needs on the other hand is far more convenient. Cars are definitely more comfortable, especially on rainy days. But even on rainy days, I often choose to ride (if it’s not a crazy storm) as it’s still more convenient.
Cars are only inconvenient in a few dense urban areas. In the places where most Americans live/work/shop/recreate there is plenty of free parking and traffic isn't too bad.
You appear to have misunderstood the Census definitions. Most of what they label as "urban" or "suburban" is hardly dense by urban planning standards. The people living in those places mostly have a surplus of parking.
The census has a broad definition of urban, which is why I also linked the Bloomberg article that is a more articulate piece on what we should define as urban. Even using that, more than 60% of Americans live in urban environments.
The question is about convenience. Cars and parking, parking lots, moving through them, being stuck behind one or two cars traveling into and out of a parking lot. Even if there is ample parking, you generally have to walk longer distances from that than you do when you bike. That is why biking can be more convenient than driving. It’s not that you have to search for parking for 30-40 minutes at both ends of you trip, it’s that driving has all sorts of annoyances, like random traffic from crashes, lots of waiting at signals, lots of waiting for others to get their cars out of the way in parking lots. That’s always been my experience driving, and that includes the very rural place where my parents live. When you travel into town for groceries, you still have to deal with moving a car through all of those situations. If I’m closer than 2 or 3 miles to where I’m going, my preference is definitely not driving, because overall it’s more annoying than biking.
