Supply and demand. If they let it be known they have 50 to get rid of then the values would fall like a stone. Releasing them to the buying public slowly, maximises the value.
Don't see the problem with buying blind as long as you don't expect any more than it meets the description. The words not the picture are the important thing. If it doesn't meet the description when you go to pay, don't pay, or quote the sale of goods act.
I wouldn't expect to get one road registered either after the problems Neil had with his overwidth tracked vehicle. That must surely limit the values compared to the more common 432's already out there and road legal.