Why write or perform a play that’s about a play (I like to call them meta-plays)? You know, the type of play where the action and plot of the play that you are watching consists of the actors portraying actors taking part in the production of a play (that you may or may not watch).
You don’t get many songs about performing music, and even fewer about the songwriting process. People don’t paint paintings about the future display or painting of painting of a painting, do they? I’m sure very few poems have been written about the writing or reciting of poems.
Not many books are about writing books (though there are instructional ones, of course, but I wouldn’t call those “art” so much as “informative”), and not too many books are about reading books (although the story-within-a-story device is fairly common, this really isn’t about the “reading” of the book).
Not many movies are about making movies (unless you count the “Making of…” type ones, but those are more documentaries about making dramas or comedies, and documentaries are an entirely different form of movie, and are almost a different medium, rather than a different genre).
I think it’s weird. Have playwrights run out of ideas? Are they collapsing in on themselves like a black hole? Perhaps they should write plays about making movies or plays about writing novels. Or, perhaps they should produce plays that are about producing plays that are about producing plays that are about producing plays that are about producing plays that are about hockey.
Everyone likes hockey-plays.