An interesting decision that I'm actually excited to see. FSDreamteam, Flightbeam, 29Palms, and FlyTampa are going to stop developing scenery for FSX to focus solely on developing scenery for P3D v4. I would absolutely love it if we saw a major shift toward developing for P3D instead of propping up FSX/FSX-SE. Yes, I've had many, many years of fun with FSX..but the number of FSX.exe stopped working messages I've gotten as the product gets filled up with add-ons is pretty frustrating.
You can read the announcement and the reasons behind it here: AVSIM topic.
"We believe the platform that will stay for us as the main sim for the next years, is Prepar3D, so we decided to make public a decision that we have been considering for several months already, since the first time we got to see the new sim: In the next months, we’ll all stop developing new products for FSX.
Some of our products that are already very close to release, such as Flightbeam KMSP or Fsdreameam KSDF, will still be offered for FSX too, and we’ll of course continue to support all our existing releases with bug fixes, but the new products we’ll work from now on, will be designed for Prepar3D 4 and future versions. We all agree this is the best decision for the future of the community moving forward, and we can only hope that our stance would result in other developers considering the same move. But we also need you, the users, to make this work."