Lives are now life styles and Main Street USA is now The Mall; what used to be Main Street sits downtown gathering human dust. Tonight's CBS Reports broadcast, "After the Dream Comes True," might have been titled "The Mall'ing of America," but that would be heavy-handed, and this program was made with elegant understatement. It is about the shopping mall as the new center of American civic life, but that isn't the half of it.

Filmed last November at the Oak Park Mall near Overland Park, Kan., "After the Dream Comes True" goes quickly and literally to the heart of matters. Indeed, the sign on the outskirts of town says, "Welcome to Overland Park, The Very Best of the Heart of America." In this brilliantly heartbreaking report, at 8 on Channel 9, a whole complex of social changes comes into new focus, and The Mall is made to serve stunningly as metaphor, symbol, avatar and harbinger.

And yet all that darned old significance never gets in the way of the fact that the program is about people and, to some extent, about how helpless they are when it comes to letting slip away things they all know, deep down, they would be better off hanging onto.

Charles Kuralt is the perfect choice as correspondent for the program, as perfect as he is for "Sunday Morning," and though the amount of screen time he gets is relatively small, producer-director Craig Leake obviously knows what's so special about him. "If you want to find America today, this is where you have to look," Kuralt says from the shopping center near the top of the hour. Right there in Oak Park Mall, an enclosed suburb of a suburb--1.2 million square feet of Controlled Environment, where the trees have leaves all year 'round and computers pipe in Muzak as if it were life-giving oxygen and clerks utter such podspeak as the inescapable "Have a nice day."

This is where today's teen-agers cruise one another and where they are officially metriculated into Shoppers. People come to the Mall to look, to be looked upon, to be looked up and down, and, says a Mall merchant, for "entertainment." At the utterance of this word, the program swoons into a montage of Mallers who seem lonely, lost, alienated, bored. They are watching, they are waiting, but for what? Orwell would look at this and say, "I told you so." A lot of smart guys told us so, but that doesn't necessarily do us any good.

Meanwhile, in downtown Overland Park, business is not booming, Muzak is not playing and the environment is flagrantly uncontrollable. Petula Clark could no longer sing of "Downtown" that "the lights are much brighter there, you can forget all your troubles, forget all your cares." The lights are much brighter out at the Mall.

A downtown barber explains that it isn't in his nature to move out to the Mall and become a "hairstylist." He just wants to remain a barber. The owner of a downtown shoe store says that kids go to the Mall to look, and they now demand an excess of things to look at (if television doesn't have something to do with this, hats are vegetables). "It isn't that they want to buy more," the store owner says. "They want to see more."

Downtown Overland Park sits on what was once the Santa Fe Trail, Kuralt points out--as probably no one else could point out quite so effectively, since Kuralt now has the folksy authenticity of an old Conestoga wagon himself (when you see Kuralt used this economically and shrewdly, you may regret ever having had an unkind thought about him). Later, an old farmer stands in the corner of a Mall parking lot, where once stood the house in which he was born, and says, "Money, money, money!" and "Progress, progress!"

He isn't sputtering bitterly, though. He understands which way the wind is blowing; and, similarly, the program stops far short of peering down its nose at the American ideals of "growth" and what one chiropractor, a newcomer to the area, keeps calling "spreading the wealth." The man praises the shopping mall as "a hey-I-don't-want-to-be-alone place where something's happening."

"This is Reagan's America, right here," says a blind school administrator. The only point at which the documentary becomes too literal is when it attempts to enhance the administrator's description of the mall as a "circus" with calliope music on the sound track.

Otherwise, it's a masterful portrait of crossroads American life. Some will watch it and see in it trends and developments that appall them, but the tone of the program is not judgmental, at least not in any Eastern oh-how-vulgar sense. Craig Leake is no tea-sipping snob; he is one of the most talented, temperate producers in network news. His work for the NBC News magazine "Weekend"--such pieces as a bittersweet, narrator-less report on how Americans behave at their national parks--was simply sensational; he was the best among the best during that program's relatively fleeting salad days.

Now, at CBS News, he has been somewhat wasted on assignments a bit too prosaic for his impressionistic talents (like one installment of the documentary "Defense of the United States"--superbly done, but not Leake's specialty). He's the kind of journalist who deserves the freest possible reign. But then, this is the kind of broadcast that inspires the utmost generosity with bouquets and trophies: to cinematographer Terry Morrison, editor Joseph A. Fackovec, associate producer Jonathan Coleman, executive producer Andrew Lack, and Howard Stringer, who headed up the CBS Reports unit when the project was initiated.

What a quietly terrific piece of work it turned out to be.

It is an almost inarguable inevitability that increased technologification leads to increased dehumanization. The question is not whether this will occur but to what degree--how much of what we think of as "our humanity" we will be able to hold onto. It may be the single most important preoccupation left to us as the century shudders to a close. Television can accelerate the process of dehumanization or it can contribute to an understanding of it. Very few of the people working in TV appear really to care about this enormous subject, but those who do, and have a feel for the medium, can engender insights that give goose bumps.

"After the Dream" doesn't view with the proverbial alarm, but it affords clarifying, even breathtaking new perspectives on what seem to be familiar facts of life. It pulls back for a wider view and moves in for a revealing close-up simultaneously, the neatest trick any maker of television can bring off. It seems to have been made by people working without any great delusions of self-importance, which may be one of the reasons that it seems as important as it is--far too important, as a matter of fact, ever to be measured in mere newsprint.