I have a VR headset, but it hasn't even crossed my mind to check if SteamVR would even work on my Mac.
Apple puts very low-end GPUs in Macs. Most models can't even be upgraded to a GPU that's decent for VR. The base $6000 Mac Pro comes with a $170 GPU! Latest maxed out top-of-the-line MBP has a weaker GPU than the last-gen lower-end GTX 1060.