Oh wow, that explains a lot, I sort of always figured it was just market momentum that meant you never see tv's with a display port. sort of like

... we need a digital video link

VESA develops DVI

... market gap for tv's identified

hdmif develops HDMI which is DVI with an audio channel

... while technically a minor feature that audio link was the killer feature for digital tv's and led to hdmi being the popular choice for tv's

VESA develops displayport a packet(vs streaming for DVI and hdmi) based digital link, it's packet nature allows for several interesting features including sending audio, and multiple screens.

... no tv's use it, while display port is better than hdmi it is not better enough to make a difference to the end user and so hdmi remains normal for tv's, you can find a few computer monitor with DP but you have to seek them out.

I will have to see if there is some sort of stupid "additional licensing cost" if a tv is produced with displayport, that would explain so much. I don't claim that there are no tv's with DP but I certainly have never seen one.