It's a set of interrelated issues. Much of the US is zoned/regulated to be friendly to drivers and not pedestrians. For an egregious example, most of Downtown LA (so not the suburbs) you can walk for 30 minutes and maybe only see 5 different stores. Because of this, American culture has stopped talking about walking. As such for a lot of Americans, walking for 30 minutes to get somewhere is absurd culturally, but driving 30 minutes to go to a store is much more acceptable.
You can see the effect even more when it comes to recreational hobbies and sports. Americans don't really just walk or bike around. Walking and biking/cycling are usually specific activities, so most Americans buy special exercise clothing or exercise gear to go (by car) to specific spots friendly for walking and cycling to perform their recreational activities and come back. Walking is still a popular casual activity in urban areas but in a lot of suburban areas there aren't even the sidewalks in place to make it safe to walk around. Most Americans only really dress/prepare for the walk from their house to the car and from the car to the store/office/destination, then back if they're not specifically out to perform their recreational athletic hobbies.
You can see the effect even more when it comes to recreational hobbies and sports. Americans don't really just walk or bike around. Walking and biking/cycling are usually specific activities, so most Americans buy special exercise clothing or exercise gear to go (by car) to specific spots friendly for walking and cycling to perform their recreational activities and come back. Walking is still a popular casual activity in urban areas but in a lot of suburban areas there aren't even the sidewalks in place to make it safe to walk around. Most Americans only really dress/prepare for the walk from their house to the car and from the car to the store/office/destination, then back if they're not specifically out to perform their recreational athletic hobbies.