I'm not sure that word works here. "Hamilton" is full of rap, and its fans include Beyonce, Jay Z, Busta Rhymes, etc. So it's a bit more mainstream than your usual musical.

You make it sound like PBS is jumping on the bandwagon after the play has become cool. In fact, PBS has been shooting this documentary for over three years, documenting its entire development process. So they've been on board since before it became cool.