For decades, thousands of Chinese investors made pilgrimages each spring to Omaha, in the central US state of Nebraska, treating Warren Buffett’s shareholder meetings for investment firm Berkshire Hathaway less as corporate briefings than as audiences with an oracle. Buffett’s retirement as CEO, effective January 1, ended a 60-year run at the helm of the global conglomerate. Though he remains chairman, he was succeeded as chief executive by Greg Abel, who joined Berkshire in 1999 and had run its...