It's a cultural thing, definitely. Some Americans take it too far, but even those who don't (many), who don't think everything in life is about winning a competition, still interpret most things as competitions even if they aren't officially so. We've got tons of sayings that subconsciously make us a winners-only culture: "Winners don't do drugs", "Quitters never win", etc.

As a teenager I was totally disillusioned with it, so I mistakenly thought winning of any form and encouraging others to try to win made you an intellectually bankrupt tool. Probably made me happier, but had the adverse effect that I feel a lot lazier than other people I know because I'm more prepared to do "good enough" rather than try to outperform my peers. Being American-born, I feel like I could be seen as a poor performer by my superiors simply because I'm not doing better than my peers.

I can't speak for the nation as a whole, but in Silicon Valley people are very competitive. There's a mentality that I too partake in sometimes of "why do it, if you can't do it well". (and 'well' has been pushed to the extreme of 'be one of the best') The influx of Asian students driven mercilessly by their parents has not exactly helped reverse this trend.

It is a good trait in many ways, it drives people to put in the extra yards when they may not have. Given that so many things in life are when stripped down a competition.

There has been argument in Australia recently over schools giving the message to primary school kids that it doesn't matter who wins in there sporting contests. I think not only does this ruin a game (when someone isn't actually trying in a game I'm involved in I lose motivation pretty quickly) but it carries over to other areas and gives a kid of close enough is good enough mentality.

For the wealth of a society it might be a good think, because everyone is pushing each other. For the happiness of most people it might be a bad thing, because only a few can win.

I can't give you a real answer, except to say that it probably involves Clint Eastwood.