Recently, I attended a provincial auction which specialises in putting into boxes the collections of dead collectors and offering them at a low price, leaving it to those who look through the box to work out its value to them. If the auction house sells a box for fifty or a hundred pounds then that’s a good enough result.
Many of these boxes do not contain collections in the usual sense; they are hoards accumulated often over many years with no system, no attempt at conservation, and so on. Most are almost worthless.
Every day since that day in May 1840 when the Penny Black went on sale, the world supply of mint and used postage stamps (and covers and cards - but I will use “postage stamps” as a general term) which are potentially available to collectors has increased EVERY DAY. Wars, floods, fires, and despatch to the municipal rubbish dump have never done much to slow the growth in supply. Even now, with so much mail being sent electronically, there are around 200 postal administrations in the world producing stamps and selling them every day, though a significant proportion of those administrations do not expect more than a tiny percentage to be used for sending mail. What percentage of stamps issued by Pitcairn Island get to be postally used?
There may have been a time when there were enough dealers and collectors to handle the quantity of material available and the daily additions to it. That is no longer true and may have ceased to be true well before 1900. There is now a very, very large inventory of stamps which are not being collected in the ordinary sense, just moved in bulk from one temporary holder to the next. Think of old bundleware which was tied with cotton thread into bundles maybe one hundred years ago and which comes to auction still unopened.
These stamps are a bit like the water in bottled water. The water costs nothing; the bottling, the transport and the selling costs money. Buy in sufficient bulk and the cost to you of a stamp drops to some tiny fraction of a cent - maybe there is a world record; maybe someone somewhere has already bought 5 000 000 stamps for something like 0.000001 per stamp.
In my view, all this creates the possibility for a very interesting hobby which I will call Salvage Philately. Salvage philately is about going through these vast inventories and picking out things worth having - rare classic stamps in really, really bad condition but which will look a bit better if they are washed; very unpleasant looking covers from which a stamp worth having can be soaked off; pre 1914 multiples of MNH ** stamps which have somehow survived in dead stocks and which can be used to upgrade spaces in old printed albums; occasional postmark interest stamps which have never been noticed.
Traditionally, all this has been called Things To Do on a winter evening. But salvage philately is really a hobby in its own right.