I have a theory some big cloud provider moved a ton of racks from SXM2 P100's to SXM2 V100's (those were a thing) and thus orphaned an absolute ton of P100's without their baseboards.

Or, these salvage operations just stripped racks and kept the small stuff and e-waste the racks because they think it's the more efficient use of their storage space and would be easier to sell, without thinking correctly.