That Ruhl thread got me revisiting Rob Kendt's list of the most produced playwrights. Just some food for thought... if you weed out the dead playwrights, the most produced living playwrights of last year were (in order):
#8: Michael Hollinger & Rachel Sheinkin (8 Prods e/)
#7: Conor McPherson & Peter Sinn Nachtreib (9 Prods e/)
#6: Donald Marguiles (10 Prods)
#5: Jeffrey Hatcher (12 prods)
#4: Terrence McNally (14 prods)
#3: Neil Simon (14 Prods)
#2: Sarah Ruhl & Steven Deitz (17 prods e/)
#1: David Mamet (19 prods)
Now, of course, what this list doesn't include is what level these plays were produced on. Both Ruhl and Mamet had plays on Broadway this year (Mamet had several, and all of his were commercial productions while Ruhl's was done through Lincoln Center). Also, if you eliminate book writing for musicals, the list changes a little bit, as Terence McNally loses one point for Ragtime and Rachel Sheinkin wouldn't be on the list at all.
So the list includes two women, no people of color, two Brown MFA grads, and at least two playwrights whose work isn't seen in New York. Also, three Pulitzer Prize winners.