No, that isn't rezlly what dealers do.
We often advertise, we often travel, we spend a ton of time on the phone answering questions for people we never see, we keep the lights on and doors open while complying with sometimes extensive governmental regulations, we often put huge amounds of money at risk in the hopes of making a few bucks per pound ...and we don't always do that.
If you could make 4 or 5 times what you pay just by having volume...trust me, EVERYone would be a dealer and the price for seng in the country would be 4 1/2 times higher.
The key to better prices (within the structure of the market when you sell) is quality, not quantity.
Think of it this way. It does me no good what so ever to have 200 pounds of low quality root that I can't get my money out of, but I can almost always sell small quantities of high quality root and make about $20 per pound. If the going price is $500/pound, that's a 4% return in a short time, and if the market is moving up before I must sell to stay liquid, I might make a little more than that. However, if the market drops, I might lose money too. As the dealer, I'm taking the risk. As a digger, I\"m out nothing if the market drops...I just don't make as much.