I agree it seems unfeasible that all those devices have failed. It also feels unlikely to me that it's anything to do with the USB hardware in the computer -- I'm not aware of a failure state that would keep so many other device types functioning correctly.

If it is an MTP issue, I would expect it to be a driver issue. I think Windows supplies its own drivers to support common device types, such as MTP devices and mass storage devices. If that driver had somehow become corrupted/missing, that may explain the issue.

However, even in that case, I would expect the devices to show up in Device Manager in an error state. That they don't show up at all may mean that my hypothesis is incorrect, and the problem lies elsewhere.

There are various results when Googling 'windows 10 mtp driver' on how to reinstall it, although none of them inspire much confidence, and they do seem to require that the problematic device appears in Device Manager.

Whatever it is, my hunch would still be on the Windows software/driver side somewhere.