The HDMI cable that came with the cheap LCD TV is probably a lower standard than the OLED needs for higher frame rates and HDR. Low spec HDMI cables are dirt cheap and easy to include, unlike a proper HDMI 2.1 cable like the OLED could take advantage of.What I find curious is I bought an expensive OLED TV and it didn’t have the HDMI cable in the box. A few months later bought a cheap LCD at Walmart and it included the HDMI cable. I do agree it should have all needed and nice when it does, but I suppose a $2500 TV vs a $200 TV is a different type of buyer? Maybe Apple knows buyers will put up with it, but like you say, it belongs in the box if it’s needed for use.
Including the same HDMI cable (likely HDMI 1.4 at best) with the OLED TV would do more harm than good, as the TV wouldn’t be used to its full capabilities. That same thing happened with iPhones (to a lesser extent) due to Apple shipping USB 2 cables with USB 3 enabled phones. I’d very much prefer underspecced cables to be excluded and pricier ones included. Sadly we most often get the opposite for those same cost reasons.
I think it’s good that Apple doesn’t include a cable with AirPods. It’s an accessory to a device that uses the same power cable. If you can charge your iPhone you probably have a means of charging your AirPods too. While Apple is certainly doing it for minor cost savings, low spec USB C cables are a dime a dozen and the world doesn’t need more of them.