I'm not sure the TV industry is about to invest in supporting a technology that will probably be long deprecated by the time most of their customers will even be able to use it. Fool me once etc
By "TV industry" I assume you mean the manufacturers of TVs. Since most of them support Android TV (which requires VP9), or want 4k Youtube as a ready source of content for their 4k TVs, and are often brands that already make Android phones, or re-use chips intended for those that do, I'd guess they'd have to do more work to avoid VP9 then to use it.
Google told us VP8 was the future, and that widespread hardware support was imminent. Then in less than a couple of years they abandoned VP8.
Next week millions of fairly new TVs are going to stop working with YouTube because Google decided to shut down the API: https://support.google.com/youtube/answer/6098135?hl=en
I'm not sure the TV industry is about to invest in supporting a technology that will probably be long deprecated by the time most of their customers will even be able to use it. Fool me once etc