This is a classic internet blowhard statement, but "when they get to $5k I will be buying two or three".
Seriously though I could see the 848 getting down that cheap in certain cases but it seems unlikely. The 999 had such polarizing looks it really hurt resale IMO. Even a 15 year old 916 is usually more than $5k today, with a 996 maybe a grand more.
If you think about it though, the 848 is really a remarkable bike. It is a stock production bike that has more power than Doug Polen ever had on the factory bikes 20 years ago.
Strip it down, powder coat the frame and wheels gloss white, and park it next to my 851...
One thing though that could greatly increase demand for the new bike while hurting resale on older designs is if the new engine requires less frequent maintenance. Cam drive through gears is a good start, and if the superbike has 15,000 mile valve adjustment intervals like the Multistrada it removes a huge barrier from keeping casual owners from considering one.
If you look at the progression of the Ferrari V8 through the last 15 years the trend to lower maintenance is clear. Prices of a 355 or 360 reflect that.