Yeah, laptops and TVs not even doing automatic brightness is even more absurd. Though Android phones have automatic brightness since forever, so why do many not have automatic color temperature (white balance)? The color temperature sensor can't be much more expensive than a brightness sensor. It's logically just an RGB brightness sensor.

Android does have a night mode which changes the white balance of the screen at sunset and sunrise, but this is just a binary thing and doesn't respond to actual ambient light.