I do a fair amount of broadcasting my X-Plane flights on Twitch, and a common theme I see in my chat and other streams are comments such as "I fly P3D/FSX because I love my PMDG xxxx aircraft", "I fly P3D/FSX because I love my Aerosoft xxxx aircraft", "I fly P3D/FSX because I love my Orbix xxxx scenery", "I fly P3D/FSX because I love my Active Sky weather/clouds", and lastly yet still a significant factor, "I'd love to explore X-Plane more, but I continue to fly P3D/FSX because I've spent a TON of money on all my addons". Interestingly, the majority of the comments that praise P3D/FSX aren't really praising the platform, they are praising the addons.
I suspect, based on my anecdotal observations, that if all of these developers made their addons for X-Plane, we would see larger hordes of pilots flock over to X-Plane. "If you build it, they will come." However, I would imagine it is a challenging endeavor for devs to take since it uses significant resources to create a addon that fully exploits the capability of the X-Plane platform, so they sit in the safety of where the money is coming in from. And who can blame them? Another suspicion I have is that if X-Plane is limiting something a developer wants to be able to do, Austin may not have been as flexible as he should be? Of course I have no proof of this, but observations over the years has me thinking this.
Anyway, I do wish that PMDG would make a 744 for X-Plane, since the current 747 selection on that platform sucks. What a shame as it is such an iconic aircraft that many of us dreamed of flying since childhood. However, I refuse to buy P3D in order to fly the PMDG 744. Nothing against P3D so much, I just don't want to contribute to the marketing evidence suggesting PMDG not develop one for X-Plane. In the meantime I'll just continue to fly other amazing aircraft like the IXEG 733, FlyJSim 732, Rotate MD-88, and the Bonanza F33a and Baron B58 w/ Simcoders REPs.