Very true about prices and availability but to all car in the market out there, every car that is owned goes down in value. There are a FEW expections but most of the time, the money spent into a car will never be seen again thats just the bottom line. Something you pay 15k from a dealership will be worth 7-9k when you leave. Thats how it is, not bashing the AE86 but this goes to all car owners out there.
Its a respectable and fair price you've put on your AE86, but if it doesn't sell you can always try lowering the price a bit by like $100.