Most Americans have a form of the culture. The details are different, but most Americans take care of their parents in some form. However because America is a mix of cultures there is a lot of disagreement on how to take care of parents and so you can always find someone of a different cultural influence who isn't doing what you would and look down on them.

There are those who don't have kids (or the kids are dead). There are also those who the kids have moved far enough away that they can't really take care of the parents like they want to. However those are not actually the majority cases.