However, devices have a lifecycle, and a lot of this hardware will still be in use in 2-3 years, where this will have moved into the center part of the gauss curve. Higher resolutions and HDR (which may push 10bit) will trip this much more than a 240Hz display [which ain't ever gonna' be mainline, really, considering we went down to 60Hz from CRTs with faster refresh rates]
CEC can be done over the DisplayPort AUX channel. I think there were attempts at an ARC equivalent but they floundered.
Another interesting question though is how much A/V connections in general will still be used in the "TV world" down the line… with everything moving towards more integrated networked appliances instead. E.g. streaming service "HDMI sticks" are now apps on the TV instead…