We had hoped for suburbia.

What we got is subtopia -- the utopian idea of city comforts in a country setting gone sour.

What we are likely to get with the energy shortage and changing life styles of the '80s are vast metropolises in which the difference between "sub" and "urb" disappears altogether.

And unless we learn how to make city planning more effective and treat our land as a resource, rather than a commodity, planners fear that much of what is now called suburbia will turn into the slums of tomorrow.

There have been suburbs for almost as long as there have been cities. Remanants of suburban settlements have been discovered outside the ancient city of Ur in Mesopotamia, built about 4,000 years ago.

There were always some people who wanted to "withdraw like a hermit and live like a prince," as Lewis Mumford put it. But in the end, the princely retreats were usually gobbled up by the growing city. The erstwhile suburb of Brooklyn submerged in the vastness of New York City. Brookland and Dupont Circle were once suburbs of Washington.

Citification of the old streetcar suburbs built before World War II, will undoubtedly sweep beyond them. I can see the tears and hear the anguished outcries as automobile-dependent subtopia begins to lose its two predominant characteristics.They are:

One: Socioeconomic homogeneity.

Two: Disorderly, wasteful land use.

Subtopia happened (it was not a forethought and thus does not merit the words "started" or "begun") right after World War II, 35 years ago. Pushed by the home building and highway industries and pulled by what was widely perceived as The American Dream, the federal government decided to meet the pent-up demand for quick, inexpensive housing, not in the existing cities, but out in the surrounding countryside.

The result, as sociologist Herbert Gans has pointed out, is often blamed for conformity, matriarchy, adultery, divorce, alcoholism juvenile TV addiction and other standard American pathologies. But it has probably given millions of American children happier and healthier childhoods in better schools and with a greater sense of space and freedom than the city might have afforded them.

Stepping up from city tenements to suburban homes that a person could walk around gave parents a sense of having advanced in the world.

In its haste to build this world, the American middle class failed to resolve the conflicts between highways and trees, parking lots and pastures, fast construction and rolling hills, chemical sanitation and pure water, inexpensive telephone service and overhead wiring.

The princely privileges defiled the hermit's abode. There had to be gas stations. There had to be shopping centers whose parking lots are five times as large as the space for doing business.Jobs in what are sometimes still called "bedroom communities" are increasing. Most of them are service jobs.

At first, small, "clean" research and development firms settled along the suburban freeways. Now, manufacturing industries and large, corporate office complexes are following. The fastest growing industry, according to Standard & Poor, is fast-food eateries, dotting subtopia like smallpox. Another survey reports that 32 percent of the land in the Washington's area's "suburban" counties is used for commercial and industrial activities.

The employes of these activities are mostly different people from the socio economic class for which subtopia was built. A good many of them still live in the city and commute to work in the suburbs, a phonemenon called "reverse commuting." As transportation costs rise, so will pressure from the reverse commuters to move closer to their jobs.

Such pressure, when not planned for in an orderly manner, causes disorder -- the kind of illegal crowding and callous exploitation that creates slums.

It has already happened in some of the old streetcar suburbs. When they lost their streetcars, they lost their value to many of their residents. Since they now had to rely on their automobiles anyway, they moved further out. The house left by one high-income family was occupied by two or three or four low-income families.

Lately, poverty and blight are creeping on beyond the old suburbs, gnawing at the fringes of new subtopias everywhere.

The outward pressure of blue collar workers and low-income people would be accelerated if a sizable number of middle-income white collar workers were to move back to the center city, as some observers believe. The belief is based on the growing number of young middle-income householders without children but with incomes doubled by working women. Presumably, they have no interest in the large suburban homes and child-oriented setting of subtopia and don't want to spend increasing amounts of money and time on commuting.

Their gentrification of the center city would do two things: It would ease some of the inner city residents out, and it would create vacancies in subtopia that these displaced people might move into. The high cost of suburban housing would, of course, prevent, such an exchange from being simiple and direct. There is a whole complicated minuet of steps, side-steps and movements in-between. It would hardly be a stampede.

But neither is such an exchange as disconcerting as it may seem at first. The American population is constantly moving and churning. One out of five families moves once a year. At the turn of this century, places like Logan Circle were peaks of luxury and refinement. In the middle of this century, Logan Circle was at the very depth of misery and depravity. Today, as we approach the end of the century, a rehabilitated Logan Circle symbolizes the enterprising urbanity of much of the American middle class.

Nor would the urban-suburban exchange necessarily be bad for the poor.Blue collar job opportunities are far more plentiful in subtopia than in the center city. Suburban schools and other services are better and more flexible. The exchange would make subtopia more varied in age, income and ethnic background.

An increasingly more varied, more pluralistic suburban population would be increasingly better able to manage the exchange without the hardships and terrifying cost the cities suffered when, two decades ago, the black immigration replaced the white middle-class out-migration.

We must learn to manage this new population exchange, if it comes, to avoid the formation of new suburban low-income ghettos.

We must face and somehow deal with the fact that just about everything that has been built in the suburbs since 1950 has been built poorly. Architects, who are now called upon to renovate 10-year-old buildings, are aghast at the low quality of the materials and the shoddiness of the craftmanship.

Well-to-do homeowners manage to keep up with repairs, maintenance and the Joneses. People with modest means may have to be helped.

The integration of city and suburbs and of rich and poor into a new, pluralistic metropolis will surely be as difficult as it seems, suddenly, inevitable.

It is as great or greater a challenge for America of the 1980s than was building exclusive subtopia in the 1960s and '70s.