As I long time S gauge (1/64) collector and operator I will give you my analysis, which may not worth much. By far the largest pool of buyers of 1/64 scale vehicles are S gauge operators. 80% of those are still running Gilbert trains and only want vehicles from the late 1940's to the early 1960's. That is why the AHL trucks sell quickly at low prices (avg about $14 retail.) The Winross and PEM trucks are mostly the wrong era for S gauge operators plus the PEM price point is too high for the Gilbert operators.
I think $2 per truck is a bit low but I suspect the buyer who made the offer figures these will sit in inventory a while until they resell. I inquired a couple of years ago about wholesaling off around half of my AHL collection. I have about 300 of them. He indicated about $6 each for the 150 because he knew he could sell them quickly at double that.
