I don't really understand this tongue-in-cheek "joke." Kroll and Mulaney both possess a certain degree of fame and notoriety from very successful stand-up, film, and television careers, and their Broadway show extended and recouped ... proof that they have an audience, no? An audience that wouldn't normally watch the Tony Awards, perhaps?
I would LOVE for them to host. In my opinion, "Oh, Hello" should be nominated for Best Play.