As others have said it is supply and demand, the value some owners are now putting on their vehicles and desirability of the product being sold.
A good example is the UK Carrier market which has seen prices go through the roof recently resulting in a large number of vehicles in varying condition coming on to the market all being valued by their owners at the same price. This has included T16's which have never attracted the value of Universals because they only saw limited use with the Canadians reducing their desriabilty. Not surprisingly the vehicles are not selling at the prices demanded.
I owned a very nice Saladin as well which I could not sell due to the limited market and I ended up selling to Withams.