Only because DJI so far stayed with Occusync 2. P3 had Lightbridge, then came Occusync 1, now 2. The three are not compatible with each other.
Oh and don't forget Enhanced WiFi used by Air 1 and
Mini 1.
So if DJI comes up with Occusync 3 for the
M3/P5, previous controller based accessories won't work.