There is really no reason to think that you have calculated the good value cameras here. What is more likely is that you have calculated the *bad* value cameras--the objects that have lost the most relative value would normally do so because no one wants to buy them; things that are desirable maintain their value. My Leica M4s cost around $400 new, and now they sell for c$1000 and more. That makes all of your Nikon examples look like serious losers, some much more than others.
One for some things, the other for the other, both for some.
It may have been expensive when new, but the rigors of time have a way of being a great equalizer.
) for a Hasselblad H3DII39 with lens in 2008, today £2,500, 10% again but in 9 short years.