Yeah, massive depreciation. Partly because they were luxury items, and every time a new version comes out, the old version drops a bunch. Partly because they don't get the best fuel mileage, so they aren't as desirable to the daily driver crowd. The early Discos like this, however, like the Range Rover Classics, have hit the bottom of their depreciation curve and won't drop any farther. They are still desired by those that want to use them as originally designed.
In good shape, this one would fetch over $3500, much like I got $3700 for my '95 Classic LWB a month ago. But it's average, so is the price.
My '01 Range Rover HSE was over $70k new, and I picked it up for a bit over $10k with a warranty and only 64k miles. Kind of like how my $70k+ 740iL was picked up for $7500 a couple years ago, and can be found similarly now for around $5k.