And it is not just in the US, but in Germany and the rest of Europe! I would say a lot stems from the "me" generation not wanting the burden and responsibility, along with the "feel good" aspect that seems to prevail in today's society.
When I was growing up my father talked about the TV (Black an White) being the "Idiot Box". Books of all kinds were in the home and watching TV was limited. Going outside was encouraged! Now it seems the parents do not want the "headache" of saying NO to their kids. Also it is being found that playing outside is better not just for health reasons, but also increases the intelligence level along with the ability to THINK!