My wife has worked in spinal ortheopaedics for more than 25 years and yes the equipment does cost loads.
For example, a single titanium screw to go into a spine (for all intents and purposes a self tapper with a special head) is hundreds of pounds/dollars each. The tools are equally expensive.
Yes there is a huge "margin" on the items but that "margin" is not profit. All of the medical companies have large R&D departments to feed plus the amount of regulation and insurance is massive.
The stuff does not make real sense for anthing other than medical. The forces used to screw something into a bone is much less than anything used in cars or such like.
Finally, no medical company would sell something on ebay. Most items are individually etched with a unique code so it is traceable, this wrench must have been "lost" somewhere along the line.