You are right. Althoug AVSIM (most off) is also FSX minded. It must be a relieve for everyone who make a little money from FSX that we can go on for at least >5 years with that old simulator and buy expensive add-ons. That was on their mind from day 1 at the release of flight and before. The FSX community did a great job to stop progression.
And the Flight devs listened to their (maybe)customers. Someone yells for Alaska we get Alaska. Someone for TrackIr we got it. Cockpits? We got it. All that is a lot of work. Time not spend on other more gamer friendly dlc. Therefore It was better they did not listen to the FSX customers.