Investors were briefly spooked last July when an M.I.T. study suggested that almost none of this is useful to businesses. Corporations had poured tens of billions of dollars into A.I., yet only one in 20 projects had succeeded, the study reported. But a Wharton study in October delivered the opposite verdict. After interviewing 801 leaders at U.S. companies, Wharton concluded that three-quarters of the businesses were getting a positive return on their A.I. investments.