For decades, NRG (short for the efficiently named National Research Group) has been a go-to source for folks in the movie business thanks to its tracking reports measuring audience interest in upcoming theatrical releases. (Wanna know how hard the next DC movie is going to bomb? They’re the early-warning system.) But more recently, the company — which until 2015 was owned by Nielsen — has been keeping tabs on the streaming world, looking at how thousands of first-run streaming...