Why is the play The Matchmaker literally commercial fiction?
The Matchmaker is based on Thornton Wilder's earlier play The Merchant of Yonkers, which itself based on the play Einen Jux will er sich machen by Johan Nestroy, which itself it based on the one-act play A Day Well Spent by John Oxenford (Wikipedia). While the earlier plays were successful, Wilder's play The Merchant of Yonkers was a commercial failure; it was panned by critics and made little money. For this reason, his re-imagining of the play as The Matchmaker used tried-and-true tropes and cues from more successful plays to become a massive commercial success; the original was comedic, but not as broadly or as specifically referential as the rewrite. Wilder styled the new play as a broad farce, with punning wordplay and ridiculous scenes (note: Joe is shaving Mr. Vandergelder):
VANDERGELDER: A man's not worth a cent until he's forty. We just pay 'em to make mistakes -- don't we, Joe? (Turns head towards JOE.)
JOE: You almost lost an ear on it, Mr. Vandergelder.
(Wilder, The Matchmaker, Google Books)
Wilder explicitly borrowed conventions and scenes from other plays, placing these into his new play to deliberately play to the audience. If he had changed scenes and themes in order to make a specific artistic statement, the play would more "artistic fiction," but since it was written specifically to be successful at the behest of a famous patron, it is better classified as "commercial fiction."