“At first glance, theater productions seem like a good fit for the streaming-platform models established by Netflix and Hulu and Amazon, since Broadway fare appeals to a passionate niche audience that can’t always make it to New York to catch a show. But there are a slew of hurdles, including negotiations with stage unions and rights holders still fairly new to working out their positions on digital distribution, and the fact that many of the productions most likely to arouse widespread interest among viewers — “Hamilton,” “The Lion King,” “Wicked” — won’t allow a capture of an entire performance to hit the Internet until after the production has closed.”