I think I should have explained this better.
What Matt Hargett is claiming is that there are many 4K HDR TVs that only support YCbCr 4:2:0 color format due to their HDMI 2.0 bandwidth limitations and not many that support YCbCr 4:2:2, let alone full RGB 4:4:4 (for HDMI 2.0b TVs this isn't a problem).
My older Hisense TV had this very problem, for example.
The problem with the color format carrying less information is that it theoretically shows colors that are less punchy with less contrast. So if the developers want to make sure that their games have great contrast and they worked a lot on e.g. tone mapping, they should push for the highest bandwidth-per-pixel color format on the TV. And if the HDMI bandwidth isn't enough for 4K60 4:4:4, then it's definitely enough for 4K30 4:4:4. So far this makes sense.
My problem with Matt Hargett's logic is two-fold:
1 - AFAIK color format on consoles isn't defined by each game. It's defined in the console's system settings. The console does a handshake with the TV to see how high the color format can be at the TV's maximum resolution and 60Hz, plus whether or not it supports HDR. The console then always sends a signal at those settings, even if the game is only rendering at 480p. My PS4 Pro is always sending a HDR signal to my TV, whether or not it's running a game that has HDR.
Matt is assuming each game will be able to do a handshake with the TV and redefine the color format on the fly. I don't know if that's possible nor if that's even a good idea.
2 - TVs that only support 4K60 at YCbCr 4:2:0 usually don't have panels that gain much from higher color formats, so there's little reason to force 4K30 YCbCr 4:2:2 or even RGB 4:4:4.
I'm also not a fan of the idea of my TV switching display modes when I transition between activities. These systems promise to have the ability to seamlessly transition between activities. Having wait for a display mode change would be quite jarring. And any TV with QMS support to mitigate this would be modern enough to support 4K60 (or higher) without compressing the chroma.