True.I've been trying to sell my iPad Pro without any luck. 128g iPad pro wifi, with smart keyboard, pencil, and AppleCare+ included for $1100.
The market for iPad Pros is extremely weak.
It's very hard to sell a computer or iPad that is only a few months old, just like it's very hard to sell a 1 year old car. Most people would just buy new if they are going to spend almost as much as the cost of a new one.
Where Apple products hold their value well is when they get old. You can usually sell a 5 year old MacBook for a few hundred dollars still.
This combined with the fact that used iPads have been in the tank as far as reselling goes for the past several years.