Over the past few years there has been a bunch of live productions of musicals for TV. It started with Sound of Music and the most recent was Grease. I wonder if they considered doing this Rocky Horror remake as a live production as well. The stage sets and dance numbers aren't any more complex than the other productions.
Richard O'Brien (the writer, who portrayed Riff-Raff in the original film) oversaw a live production which played in theaters across the Europe last year and later aired a few times on BBC America and UK networks. Since Fox owns the film rights, they can't issue it on DVD, but it's on You Tube. It was shot on stage in front of an interactive audience, and it's infinitely more satisfying than the 2016 TV movie. Check the links below for more.
It felt like it was originally supposed to, but they couldn't make it work, or weren't confident enough. Otherwise it just looked really oddly staged if it wasn't meant to be live at any point.
That's what I was getting at. My guess is they probably started this project with the intention of it being live like Grease. They went sorta half way by including the theater audience. Since the audience interaction is what made Rocky Horror a cult hit it sure seems like this would have been a perfect candidate for the live format.