NIB pinball are now depreciating like normal. 10-15% off the top. Evan a game like AC/DC Vault is getting offered up at 11% off purchase price within weeks.
This is the cost of the hobby. For a while, it was free. And that was AWESOME. You could buy a game, and sell it a year later for more! You didn't even need to be that careful because prices were going up so fast.
Now we are back to reality. There is a tax for NIB. You try to sell it for what you have into it, and it sits because (hint), you paid too much. Situation normal.
(And as always, a bargain price will have plenty of interest)