This, at least ours have big restrictions on reselling since they were paid for using government grants- we can’t just resell to the public, so if another department doesn’t need them, they just sit around in drawers for a few years until they get scrapped. Eventually some are listed on auction sites, but at that point they’re worth so little- even $500 isn’t enough to justify the time spent wiping, listing, etc. and potential liability if any financial/HIPPA info is left behind.

Once AppleCare wears off our machines are replaced anyway. We’re allowed to just keep our old ones, especially for international travel (computers can be searched at borders, this way we only load what’s essential and if it’s stolen it’s not a big deal).