It depends heavily on region, but in the suburbs most Americans have room for something that wouldn't be easily affordable in an urban Japanese home (or urban anywhere home, i suppose). Maybe a lawn or backyard, maybe a pool, maybe a garage that can fit more than one car, maybe a driveway that can fit your car while your garage is used for something else, a house big enough to have a room that you don't use every day, and so on

I personally would vastly prefer a walkable, affordable, safe, dense urban region over a lawn, a 2 car garage, and a backyard. But not everyone would agree with me, particularly for some who would say that dense and walkable is a negative rather than a positive.

They are though. This varies regionally, but they're both multimillion dollar industries that push very hard to make their goods affordable to increase their available customer base.

I grew up in a lower middle class neighborhood, and every other house has a bench and some weights. Many of the families saved up for a treadmill or elliptical, and woe betide the child who thought they could use it. Someone on every block(usually more wealthy than the area average) had an above ground pool, and the neighborhood kids would go over and hang out there all summer.

Its not super crazy. When you consider the number of homes that have home gyms, or pools, or basketball hoops, trampolines, or swing sets etc. that people have, its a large number of homes. And even for those who don't, most houses in America are built such that one could buy one if they want.

I grew up in suburban Indiana, and when I went home to visit my parents, I counted it up and literally over 1/3rd of the houses I could see from their front porch had a basketball hoop in the driveway.