It does appear, from what I have seen, that there is possibly much less demand for the
Phantom 4 Pro than there is for the Mavic Pro. I'm seeing some buzz about the
Phantom 4 Pro, but definitely not to the scale that there was/is for the Mavic Pro.
I'm guess it is due to the timing of the announcement. The Mavic Pro announcement came out several months prior to the holiday season when people had some spare cash to spend prior to Christmas. Now that Chrstmas is a touch more than a month away, people are a little tighter with their money, especially if they've already bought the Mavic Pro or recently purchased the Phantom 4.
The good news is that, with the lower demand (if that is the case), there should be no shipping shortages.