How did American Ballet Theatre get to be a more interesting company than New York City Ballet? It’s an astonishing reversal — who could have dreamed it,” wonders Robert Gottlieb. “This has been an A.B.T. season that’s given us Ashton’s Sylvia as well as the best squad of ballet boys in the world — and Diana Vishneva. Perhaps even more important, the company is helping — or, at least, allowing — some of its dancers to grow before our eyes, unlike the situation at City Ballet, where talented kids roar in from the school and stagnate … if they don’t fall apart.”