Unless I missed it, there was never any sort of official announcement that DJI has discontinued the Phantom 4 Series. True that they have discontinued the Phantom 4 and Phantom 4 Pro. True that the Phantom 4 Advanced and Phantom 4 Pro v2 have been out of stock for months. However, that should not be taken to mean that the Phantom 4 line is dead, or even more broadly the implication that the Phantom line in general is dead.
I love my Phantom 4 Pro crafts. They are my workhorses. However, I can't assume that they will be produced forever. Technology moves forward. That is inevitable. I loved my very first Phantom 3 Pro, but I never expected DJI to produce those forever either. Instead they progressed and built the even better Phantom 4 Pro.
DJI has done very very well in continually producing new products which consumers want and enjoy. I don't believe they will abandon the Phantom market. I don't know what is in store, but I fully expect it to be a step forward, and not a step back. It could be a Phantom 5, which is even better than the Phantom 4 Pro. It could be a Mavic 3 that somehow crams all of the Phantom 4 Pro technology (and camera quality) into the Mavic airframe. It could be that elusive Phantom with high quality camera and interchangeable lenses. We just don't know. What I am fairly confident in, is that DJI will continue to have a product line that fills the gap between the Mavic and the Inspire.