Us old people have the idea of peripherals as input (keyboard, mouse) or output (monitor, printer) - but they've all been input/output for two decades or more; and Thunderbolt and friends are much more like an Ethernet network (reliability of Wake on LAN, anyone?) than they are simple point-to-point connections.

Meaning - anything could be the device preventing what you expect to happen, even if it looks like it should be impossible and have nothing to do with it.