The automotive world has changed in the three months since The New York Times first revealed that Sergio Marchionne had asked Mary Barra to meet for a date to discuss a merger . Marchionne raised the issue again this week, telling Automotive News that though a combined Fiat Chrysler-General Motors could generate $25 billion to $30 billion in cash in a 17-million unit U.S. sales year, Barra and company have not returned his calls.