As Tom Naratil prepares to leave UBS , he says he’s departing a business radically different from the one he joined nearly four decades ago. “Frankly, my first job, as a government bond trader, has been completely digitized at this point,” he quips. Since joining the training program at predecessor firm PaineWebber in 1983, Naratil has observed the evolution of stockbrokers into advisors, the emergence of robo-advice, and his firm’s pivot to serving wealthy and ultrawealthy investors. In an interview with Barron’s Advisor shortly before his last day of work on Oct. 31, the financial-services veteran, who recently stepped down…