AS ANYONE WHO watched the opening ceremonies of the XIII Winter Olympiad last week knows, those who plan such things do not think small. The festivities were joyous, imaginative and expansive, as well as costly. Why is it, then, that those Americans who are so deeply involved in this winter's activities cannot think on an equally grand scale about the activities of next summer?

The chances that American athletes will participate in the Moscow Olympics are practically nil. Everyone knows that except, perhaps, the members of the International and U.S. Olympic Committees. Everyone also knows (except perhaps for those same people) that the athletes who will be denied a chance to complete for an Olympic gold metal deserve the best possible alternative event.

Even F. Don Miller, executive director of the USOC, admitted the other day that his organization was thinking about what could be done for those athletes. He had even, he said, talked to the television networks about coverage of some special summer event to be put on by the USOC. But of course, he added, it would be for for American athletes only.

That suggestion doesn't even qualify as thinking, let alone as thinking big. An "American only" event would be nothing more than what occurred last summer at Colorado Springs. In fact, it would be even less than what occurs practically every year in most sports -- a world championship competition. And it would provide nothing for those athletes from other countries who will be following the lead of the United States and staying away from Moscow.

The fear of the members of the USOC, we are told, is that the IOC might punish the countries and the athletes who participate in an alternative to Moscow. The athletes might be barred from future Olympic competition and Los Angeles might be stripped of the 1984 summer Games.

This can be regarged as a legitimate fear only by those who think the Olympic Games are sacred and that the plutocracy that controls them is omnipotent. But the importance of the Games and of their self-anointed guardians rests entirely upon their being able to attract worldwide participation and -- is it all right to say it? -- worldwide newspaper and television coverage. Without either, the Games and the IOC become no more than a tinkling bell. Who would care about the outcome of an "Olympics" in Moscow involving competitors only from the Soviet Union and those countries closely associated with it?

Several universities in this country have already offered their services and facilities to the USOC for use in a major sports extravaganza next summer. If no one else in the world wants to be the host at such an affair -- open to athletes of all countries whether or not they compete in Moscow -- one or several of these offers should be accepted. If the USOC cannot bring itself to do that, if its members are so tied to the past they cannot recognize the mire into which the IOC is sinking, it should abdicate its role in international sports and tell the national sports groups that belong to it to form a new organization to run next summer's free Games.