This is a great example of the collective forgetting that goes on in the hobby. Theatre kids have been in the hobby for decades. I’d be curious to know who’s making this claim, as anyone who has been in the hobby for a while would know it’s absurd.
TTRPG Actual Play did not create Theatre Kids in tabletop roleplaying.
It just gave the Theatre Kids something to cite when they came to a new table.
Which (not to put too fine a point on it) resembles other examples of “what you can name you can see, but that doesn’t mean it didn’t exist before”