Most Americans' lives would change forever if they had just $1 million, not to mention being paid lucrative salaries that spanned millions of dollars over three to four year spans. This would enable them to live comfortably for the rest of their lives while working a menial job, if they even chose to do that.
If every American was suddenly given a million dollars, I'm willing to bet that most of them would not be responsible and put it into savings and investments. Instead they would use it to buy expensive toys, extravagant vacations, hookers and blow, etc. Or they'd quit their jobs and live off the money for as long as they could. Within a year most of those people would be just as poor as they were before being given a million dollars.
Hell, there are people who have won lotteries with jackpots in the tens of millions of dollars, and within a few years they had pissed it all away.