THAT QUESTION was the headline of an article in this newspaper last Sunday, and it was answered affirmatively, and in a thoughtful, detailed and disarmingly persuasive way, so it cannot be lightly brushed aside. A growing number of responsible officials and concerned citizens have been asking themselves that question as Metro's building costs have steadily spiraled upward, and it has become increasingly apparent that heavy operating subsidies will be needed to keep Metro (or any other public transportation system) running. While we do not have room here to deal with all the questions raised by Gabriel Roth, a British student of urban transportation problems who now lives in the Washington area, we would like to address some of his more important points.

Mr. Roth prefaces his case against Metro with a recital of what he thinks were "fundamental" mistakes in the initial selection of a rapid rail system. Frankly we think this is not a point worth arguing, with the benefit of 12 years hindsight - mostly because we don't think the point has much validity. In our view, the original decision made sense at the time, which is about as much as you can ask. Despite the second guesses of today's revisionists, the decision was reached in a thoughtful and responsible way, after careful consideration had been given to all known alternatives. If it appears today to have been wrong - and we are not prepared to conclude it was - this is largely because of developments over the intervening years that could not, we believe, have been confidently predicted at the time. We can find no evidence that adverse factors were readily perceivable in the 1960s and simply ignored.

Nor is it of much use now to propose unrealistic changes in Metro's future design. There is, for example, the suggestion that the tunnels, stations and track already built be converted for buses instead of trains. There can be no doubt that any such proposal flies in the face of political reality; the public simply isn't psychologically prepared to pay the price - in delays, upheaval and financial support - of a radical departure from the present, long-promised grand design. We strongly suspect that the changes proposed by Mr. Roth also fly in the face of technical reality. It would be no small job, to put it mildly, to increase substantially the ventilating and air-conditioning systems, widen the stations and at least some of the tunnels, and build access ramps from the existing right-of-way to highways or newly built busways. A scenario under which that is accomplished after closing a system that has already begun to change the transportation, shopping and eating habits of thousands of people borders on fantasy.

Similarly, it does little good to try to compare Metro to subway systems in other cities.San Francisco's disastrous experience with BART has practically no relevance here. BART lacks the downtown station network that Metro has and so far, at least, has operated in competition with, instead of in conjunction with, a bus system. Indeed, Metro is carrying almost as many people on its two short lines as BART is on a complete system.

Two aspects of Metro's future, however, do deserve attention. One is its ability oto fulfill its promises on the reliability and efficiency of its equipment, operations and planning. The enormous patience that Metro's customers have shown is going to wear thin unless the operating bugs are eliminated. The other question is whether all of the outlying arms of the Metro system should be completed. There is no difference, in theory, between ending a Metro line at National Airport or at Franconia so long as both are served by feeder buses. But deciding to bobtail the system by feeder buses. But deciding to bobtail the system that way, as many people are now suggestion, is not so simple as its sounds. There are problem involving traffic, parking, rail yards and already planned development, not to mention financial contracts with suburban communities.

It is quite proper that consideration be given to proposals to change Metro, as is now being done in the analysis of alternatives required by the Department of Transportation. But it is essential that such consideration take into account the realities of the world in which Metro exists, a world in which details - such as where you park the trains at night - count as much as broad concepts and in which delays for further study lead to inordinate cost increases.