The HDMI Forum, responsible for the HDMI specification, continues to stonewall open source. Valve’s Steam Machine theoretically supports HDMI 2.1, but the mini-PC is software-limited to HDMI 2.0. As a result, more than 60 frames per second at 4K resolution are only possible with limitations.
Console manufacturers all just need to switch to displayport to encourage tv manufacturers to do the same. No one’s going to not buy a ps6 or steam machine because they have to use a little dp-hdmi adapter, but they might be a little more likely to choose a tv that doesn’t need an adapter over one that does
Sony would probably create a proprietary standard before they’d switch to displayport.