Travel the country yourself to jumbles searching for the exact items you want - or do it from the comfort of home.
If you go after the open for public starting time, nearly all the "good" stuff will have been bought up by the dealers (posing as sellers to get in early) to sell for profit, a huge profit in some cases. Of course anyone is free to book a stall at a jumble, put unsellable junk on it, and leave it unmanned whilst they go round buying up stock.
It's not as if the dealers are digging stuff out of the ground, they are buying stuff that would have been bought by somebody anyway at a much lower price. I'm not saying they don't provide a service, they obviously do: they're a one stop shop who'll have a range of products, a place to sell to if you want a quick and easy sale, in the case of HS (not sure about other dealers) good description and background info (although biased to justify inflated prices). So they appeal to people who are time and/or knowledge poor but money rich, prefer to buy from the comfort of their keyboards, prefer not to deal with random sellers who don't have a commercial reputation to maintain, prefer to have the safety of buying from a known dealer.
So the question is does all that justify their high inflated prices? Obviously enough people think it's worth, or maybe they think they either have to pay up or go without. They also inflate prices to a global level by selling internationally.
I'll just add I'm taking about second hand stuff, I would guess NOS dealers source their stuff in a different way.
He does an AWFUL lot of miles travelling to jumbles to acquire stock and then strips, checks, cleans and photographs it prior to selling.
If I'm reading it correctly, are you suggesting the above adds value? I don't agree. You could say (depending on your point of view) buying up stuff from lots of disparate sellers and putting them all in one shop to sell is adding "value", but all dealers do that surely. But stripping, cleaning and taking photos? That's all just part of running the business, like writing an address label, cashing cheques, ordering a courier etc.
