For good reasons.

I have ALL of the RC flight sims out including Phoenix 4 with all updates applied.

Many users are complaining about not being able to set it up with their own transmitters with Phoenix... even in this forum.
( I got all of mine to work though... )

The flight models are a bit quirky and a common complaint is that they do not react like the real deals.

The "3D" airfields are a joke... something that Aerofly does best although it is impossible to create your own in that sim.

For yucks TRY to set up a snap flaps mix in Phoenix with dual ailerons & differential.

You can't do that in Phoenix nor Aerofly, but it is trivial in Realflight. Nah, Aerofly and Realflight have it over Phoenix.