NEWSWEEK SPOTLIGHT ON BUSINESS Who Owns Industrial America Around the world, Soviet "agitators" -the evangelists of Communism-harp on the theme that U.S. capitalism is the avowed archenemy of the people. In America, says the agitators' key handbook, all corporations are "in the power of a· small handful of billionaires-the Morgans, Rockefellers, du Ponts, Mellons- the '60 families' of contemporary slave owners . . ." fortunate people have an interest in some 4,600 companies wo...