Is it worth dramatically more in an eBay sale?

These machines were:

A. Ludicrously priced in this configuration new to begin with

and

B. Have been thoroughly "osbourned" by the ARM macs.

although we don't have a direct replacement machine (e.g. ARM mac with PCI-E slots), a Mac Studio off the Apple store floor will outperform it in so many tasks at a fraction of the price, power consumption and size.

I wouldn't want to buy this computer 2nd hand at any price other than fire sale low, personally. For those of us who lived through the PowerPC to Intel transition, the speed at which G5 PowerMac towers became worthless was pretty impressive and I suspect the same happens for the intel - ARM transition, if not more so.