This time last year M15s were going for $350-$600. That's a much more reasonable price for this piece of hardware. The $1600 prices were an aberration. Before Ripster breaks into microeconomics: eBay auctions don't represent the "supply vs. demand" curve. To get the price up all you need is two people willing to pay near that price, and have a perceived supply of one.
For comparison, take the IBM T221, another piece of hardware that regularly goes for $1000-$1600. It's a 22" 3840x2400 monitor that still compares favorably in other respects to many high-end monitors available for around the same price. It won't be obsolete until desktop 2160p monitors arrive. Those will be priced in the same range. And that may or may not happen soon. So the price makes sense as a "market" price.
The "market" price for an adjustable mechanical ergonomic keyboard should reflect the premiums people will pay for each of those features, plus perhaps an added value of having all three together. Does anyone reasoably believe that's more than $600? Higher, inflated prices probably come from collectors of keyboards and/or IBM hardware. Let's put things into perspective: $510 isn't "cheap" at all.
