Pondering on this I think it's a form that goes back further, if only because I can recall a hypothetical one posited by my darling GB Stern in one of her 'ragbag chronicles'. She was riffing off something that was around in ?30s/40s and suggested (though also remarking it would be Very Long) novel which starts in theatre, First Night impending, only seats which are taken are those for the critics: and by the time curtain is up, all are filled, standing room only, story is how audience all get to that state, with presumably cameos for the thesps.