maybe im not making any sense... but this is just one step I use in looking at any questionable sign.
It seems to me the problem has become that ALL signs are now "questionable" for many reasons that have been talked about almost daily on this site.
Actual sale prices of items over the past 3 years supports this theory. They have come down and I believe they will continue to come down. Compare our collectibles to Red Wing brand (and similar) pottery and crocks. Prices were sky high, now you can hardly give them away. Same with tractor seats, hit and miss engines, sports memorabilia, etc. Prices are driven by demand. When a market is saturated with counterfeit items and crooks, the demand goes down and so does the price of authentic items. Just because a sign once sold for $1500, doesn't mean squat today. All collectibles are just things. Things which NOBODY NEEDS, but which they desire.
Personally, I now avoid porcelain signs and petroliana in general for resale purposes. Don't get me wrong, I love the stuff and still want to buy what I can that's actually a deal, but it's become too volatile. I've became gun shy due to the scammers and repops marked/represented as originals being sold everywhere including here (this post as an example).
As an ebay seller, I will openly admit that the majority of porcelain gas/oil signs I've sold have been at a loss. This is not because I'm buying them too high, but because the market for signs that are actually available and not in private collections has somewhat tanked and continues to do so. There is no room for the prices to go any higher and it is my opinion that the market has capped. Not to mention the "deals" have been dried up for some time now. In the past I have bought and sold them because I love them (who here doesn't), but they are not the items bringing any real profit in re-sale.
Many of the old timers in the hobby may still think prices are high and yes -to you they are. But to the people who started collecting in the last 3-5 years, the prices are now lower, and they continue to fall because there is no more room to go up. Eventually, guys like the jersey boys will end up taking losses on most of their inventory unless they want to sit on it forever and ever.
I question how they can continue. Most signs sit and sit. Some they sell and make some money, others are auctioned off because they need cash flow. Eventually, they will have sold everything but for what? Profit? At the end of the day I doubt it...
Sad but True (in my opinion)