> Possibly because a developer hired to write something around usbip would cost a lot less. https://usbip.sourceforge.net/

Would it? For the sake of discussion, I'll assume "thousands of raspberry pi's" = 2,000 RBpis, or something around $10,000 in license fees.

I don't know anything about either project beyond the links shared by you and the root comment, but based on the information at each link and the assumption of $10,000 spend:

I would choose the one time cost of VirtualHere's purpetual update license and release cadence over a some short dev for hire contract to write some unmaintained wrapper code around a sourceforge library that hasn't been been touched in over a decade.