While I almost completely agree with you, never underestimate the power of using the right tool for the right job. HDMI is actually far more resilient to signal corruption in my experience than display port since it implements TMDS and the cables are more commonly well shielded since they expect them to be used in device dense environments, which isn’t really applicable to anyone familiar with technology (don’t group up your cables next to something with significant RF noise/leaks, duh.) but does matter for the end user use case these see. The fees hdmi charge are a scam though fr and we could ask better from the industry.
Multicast still requires more expensive less widespread bandwidth than sending out analog signals ota & shooting off a few packets of encryption information every now and then. US infrastructure has rapidly improved over the past few years, but we’re still a farcry from anything robust and reliable enough to serve the people benefiting from this type of content.