Maybe I'm wrong, but I think you're comparing two different scenarios in your mind and considering them the same. Most of these "inflated" price used saws have been rebuilt with new parts which costs money and labor that isn't free. Then you're trying to compare that price to a used saw price that you run across in the condition these fellas are also buying them at before the aforementioned money was put into them. Sure there's saws out there in great condition that can be flipped with no money or labor put into them, but again they would be in the condition after adding time and money to a much cheaper used saw.
My point being, yes you can find used saws in the price range you speak of, but no they won't be in the condition that these guys are selling them at, and if they are, they are few and far between, not the norm, which takes time to find them and time is money. Just like you or I wouldn't work for free, these fellas in the used saw sale business also expect to get paid. This doesn't even include the time to post the ad, pictures, answering questions, packaging, shipping etc.
The convenience of not having to do anything costs money which the customer is willing to pay, that's the way it's always been. Lazy people pay more. If I want my steak cooked for me and not have to do the dishes, I’m going to pay more than if I did the legwork myself. The supply and demand of mechanically sound used saws is what sets the market price, not a “pump and dump” scheme.
I have 3 questions that I would appreciate an answer to.
1. You said you would sell a 372 for $300, which is 1/3 the price of a new one, do you feel it's in the condition both mechanically and cosmetically that a 372 is that would bring a much higher price, the price you're calling inflated?
2. Would you mind giving a more detailed mechanical description of this $300 372, as in, why is it out of service under your bench and can you post a picture of it?
3. Do you feel a $300 372 in mechanically sound condition, that will last many many many hours, is easily found with very little legwork involved?