I don't understand it either. Two scenarios make sense to me:
Somewhat probable: everyone in a department got upgraded, no exceptions. 'This is a really nice PC, but the boss says it has to go.' (There were about 100 i5 9th gen mini PCs (still OK), and 500 t640 thin clients in that same load.)
Less probable: some department got closed and cleaned out.
> Are you in some rich part of the US?
Pittsburgh, Pennsylvania. Not particularly rich (rust belt), but healthcare is a significant part of the local economy. About 90% of healthcare here seems to run on HP, but Dells can appear.
> Here in Europe I sometimes see hospitals and doctors practices using 10+ year old PCs and still rocking the old 17-19 inch 1280x1024 CCFL LCD monitors from like the mid 2000s.
My stomach turns seeing the dozens of 24" probably 1080p monitors we scrap every day. Pretty much all are significantly scratched when they come off the truck, otherwise reselling them might be good business.