At the risk of turning into Quizzy, prices for these are now totally nuts! £3,750 is ridiculous.
Well, they don't do new ones anymore, so I guess price is only going to increase.
It's an interesting question. Same goes for vinyl records. The age of people who are interested in MK is going up all the time and eventually they will die off. Similarly, there is a lot less interest in younger people for guitars than there has been in the past.
So at some point, there will be very few people who are interested in owning a Knopfler guitar, or a Clapton guitar or a Jimmy Page guitar, and values will likely fall.
Same was happening with Elvis memorabilia but the recent film might reverse that trend.
https://www.theguardian.com/music/shortcuts/2017/may/07/elvis-presley-memorabilia-plummeting-in-price
This has been said many times about my other passion, motorcycles of the 1970s/1980s. Like some guitars motorcycles of this era have shot up in value over the last few years, guys in their 50s/60s re living their youth maybe but will the arse drop out of the market when we are all in homes/dead?
I doubt it, there is still a strong demand for Brough Superior, Vincent Black Shadow etc and the original owners will be long gone, same goes for 54 Strats 59 LPs etc.
Quality /rare products will always be in demand.