You are talking about right now.
I imagine the majority of TV's released in 2021 (after the consoles are released) will have HDMI 2.1
this is the thing that a LOT of people on here and other forums seem to forget we are not the majority or the target audience for these products, how many people who have working 4k tv's are going to go and drop say £1k+ on a new one next year ?? maybe in a couple of years the two technology's will marry up with games that can actually take advantage of 4k120 and its worth it to spend on a new tv, but for now like the 8k spec its all nice marketing waffle.
and as for next year more models will have hdmi 2.1 sure, but dont expect it in the majority as the majority just yet as outside of the next xbox and pc gamers (ps5 probably to follow who knows) its not a big enough thing. same with 8k.