We are all going to have our different opinions and rationale about this topic for sure, and that is 100% completely understandable. But then again, we are currently financially invested in our vehicles so our opinions are slightly biased.
I am specifically saying that to new potential Tesla buyers or the general public, the P85 has been rendered obsolete. This is especially true if someone today decides he wants to go out and purchase Tesla's performance car, which is now the P85D, and not the P85. The P85 will now only exist in the second hand market and can not be purchased as new, kind of like when a new 2014 HDTV is released and then pulled off the shelves and replaced with a newer/better model. This is exactly why HDTV's depreciate extremely quick. You can also look at it like the P85 is the iPhone 5S and the P85D is the 6. The Model S is great, but it has the same sentiment as most other technological gadgets out there, especially the way Elon goes about hyping the "newer, better" versions.
At the end of the day the P85 is a great car, and will always be- but it is disappointing it was retired so early on in it's life.
Just the other day a guy was walking out of Albertsons as my wife and I were loading groceries and he said "Nice car.. I love those. Is that the one that can drive itself?" I replied "No, my car was built right before the autopilot stuff was announced" and his reply- "Yep, I read that the newer cars are coming with those features" Awesome.. here I was sitting with my "brand new" P85, no license plate yet, and some guy referred to the self-driving cars as "newer" and in his mind I had the older one. This is a great example of how these features are being marketed and hyped making potential Tesla buyers and the general public thinking of the Model S like a smartphone- when new features come out, the previous version is "old".