Folks, there are many ways to shoot b-roll.
Sometimes shows just set up a few cameras at the back of the house, and then the ad agency edits excerpts together for various purposes (montages, 30-second spots, 15-second spots, etc). MUSIC MAN has gone full-out –– crisp 4K footage that was obviously shot at a specialized video-call without an audience, and then edited together to sort of resemble a film trailer. Per Equity, there are limits to how much b-roll can be released to the general public, and I am too brain-fried to remember those specifics at the moment.
The agency will have full recordings of the show sitting on a hard drive somewhere (shot from multiple angles) and also HD audio. The stage manager will have a video of the show for training/archival purposes, shot from back of house. These things are true of nearly every single Broadway show. They will never be released to you no matter how much you whine about it.
On a personal note, the b-roll of MUSIC MAN just underlines my problems with the production –– its ultra-high sheen and bright lighting, its clunky set design and saturated colors, Hugh's knowing winks to the audience, Hugh's very 2022 haircut. Some shows don't translate well to b-roll; it's an entirely different medium, especially when you're getting up in their faces as this is doing.