It was a perfect weekend for generation-watchers at Forest Hills. There, in less than 48 hours, Billie Jean King, 35, was beaten by Chris Evert Lloyd, 24, who was then beaten by Tracy Austin, 16.

Chrissie put the whole thing into perspective when she benignly patted the teen-aged victor on the head.

I couldn't help noticing that Tracy Austin displayed an utterly uncomplicated determination to get into first place, to become No. 1. Nor could I help noticing the crowd. It changed allegiances, sided with the contender, grew more and more excited at the prospect of unseating a champion and crowning a new one.

The whole thing reminded me of a suspicion I've had for some time: that sports contests have become a kind of model for the rest of our culture. No, I am not just talking about winners and losers. I'm talking about living in the age of expendability.

Not long ago, in discussing this with friends, we came up with the wry notion that if you become truly successful in America, you have two options: you can die immediately or become a has-been.

This is not exactly a comfort to the contenders, but there you are. Our country markets has-beens as if we were doing piece-rate work for the manufacturers of Trivia games. We churn out Golden Oldies and Where Are They Nows.

Andy Warhol -- another Golden Oldie -- once said that someday everyone in America would be famous for 10 minutes. He was wrong. But someday, at this rate, no one will be No. 1 for more than 10 minutes.

It's easy to understand why athletes are replaced like new parts. They're in a business that depends on the human body. But it is less clear why this happens in fields that depend on the mind, talent or even, for heaven's sakes, experience. And I wonder if it doesn't have something to do with sales.

People have become our products. The "stars" -- whether they are athletic or political, literary people or entertainers -- are marketed and marketeers, hustled and hustlers.

It doesn't take a whole evening in front of the tube to see that brewers are selling ballplayers, not beer. Similarly, in Hollywood, the industry wants to sell stars, not movies. In most places, they still force theater owners to bid on movies blind -- without seeing much more than the cast.

Meanwhile, in New York, the publishing people are selling authoris, not novels. They push "a" Taylor Caldwell or "a" Robin Cook, a byline and not necessarily a product.

In politics, of course, they package.

We know all this, but what we don't know is that there may be an inverse relationship between exposure and endurance, publicity and productivity, selling and sales credibility. The natural obsolescence of an athlete becomes the built-in obsolescence of every No. 1.

Admittedly it takes a lot longer to master politics than a two-handed backswing. There aren't many 16-year-old politicians in the wings. But, if you remember, less than four years ago Jimmy Carter was an unknown, and now we are told he is a washed-up. The man who made personality the sales issue complains now that no one pays attention to the real issues. He is paying for his sales campaign. He, too, looks expendable.

Norman Mailer once wrote that the "first art work of an artist is the shaping of his own personality." But the very public shaping of his own personality has warped Mailer's art.

To a certain extent it is our fault. We run most of our stars, like Joe Namath, and dump them when their knees go or our interest wanes. We devour their lives in People magazine and their talents on television and their time on talk shows.

We gobble them down like pistachio nuts and throw away the shells. Then we demand more. We end up with 100 has-beens for every Carl Yastrzemski and 500 crashed starlets for every Katherine Hepburn.

I think we may have too many mutually exploitive relationships with public people. We have too many one-night or one-season or one-term stands.

People have become our most expendable product. We have become cynical toward every salesperson and expect a quick turnover in the inventory of idea-makers and problem-solvers.

Today, even the eager contender may discover that success in America often takes the same course as an overhead smash.