Well, Steam statistic tells us, that FSX has ~3,406 users online per day, and X-Plane 10+11 ~579 users online per day.
I know that stat excludes P3D and versions of XP bought directly from Laminar. Still, I think that stat is somewhat close to reality. I think that, unless X-plane user base will grow close to FSX user base at least, we should not expect 737 from PMDG.
Anyways I use both sims, depending on current mood :D
I do enjoy FF on par with PMDG though. Wouldn't say "it's a joke"