Good article, but I think the numbers are often skewed by impatient people that are always in a rush to get a new car.
I have a friend that had a '05 Shinka (man that's a pretty car) and he managed to get $25k for it from an out of town buyer when most GTs were going for $20k and lower.
If you stay firm on your price and take your time when selling a car you'll find the right buyer (one that can appreciate what it is). I even made a profit on my low mileage RX-7, but it took 6 months to sell.