We need more DisplayPort enabled devices. FireWire failed due to gate keeping. Thunderbolt surely isn’t a success thanks for the same reason. HDMI should fail for this reason even if it’s unlikely at this point.

heise online

Valve: HDMI Forum Continues to Block HDMI 2.1 for Linux

Technically, the Steam Machine supports HDMI 2.1. However, Valve and AMD are not allowed to offer an open-source driver for it.