Debate on the GMB often results in assumptions being made on minor side-points, and care is needed when making a statement about other individuals based on these.
most collectors deal too, very few can afford to forever buy... whether it is for money or space, or just because one is bored with a piece? What eBay has done is to make it a lot easier for the collector to sell and particularly the smaller low value pieces which at one time were virtually unsellable except as parts of large lots.
For example my stamp collection - I was offered one thousand pounds by a dealer, since then I have sold about 40% of the collection and taken around 5,000 via web-site and eBay. Nice thing is that as many collectors have bought the common pieces as the rarer pieces so that the spread still remains good with rarer and common material.
The map collection was declared unsaleable by the dealers, as a lot, so I sold first singly and then some batched lots. Some 60% of the maps have sold.
Most of the glass I sold was high ticket stuff so more distorting for the collection, but that was a choice of necessity rather than anything else. My one remaining important and perfect vase is now up for sale too - no fixed price and I am as happy to sell via a dealer as any other way - except I choose not to use eBay in this case... might have to if I don't get a realistic offer soon.
It never occurs to me to try via a Glass Fair. Of course when I was in the trade those things did not happen and you only had half a dozen selling outlets in the whole of the UK, supplemented by a lot of auctions and those dreadful cabinet warehouses where the sellers were at work and buying was near impossible. So to deal successfully you needed a shop to keep things turning over but also to buy stock. My first few years in the trade were a travelling frenzy, constantly hunting but after a few years 90% of the stock came through the door - with 2 market outlets, I never felt the need to tour in fairs. When I started to specialise, I cut down to the shop and Portobello with all the glass at Portobello. People would visit regularly from as far away as Scotland 3 or 4 times a year - eventually I dropped the shop and just continued one day a week at Portobello. By then I only looked in shops/markets that I was passing by - most of my stock was brought to me at Portobello, or by appointment elsewhere.
I found this debate interesting as it threw up many surprises and puzzles.