I don't much about audio, but wouldn't binaural stereo only work if the two speakers are to the sides of you, like with headphones? Would this work from a TV that's an ambiguous distance in front of you?

As a side note, Windows (and Xbox) support Windows Sonic, Dolby Atmos for Headphones, and DTS:X, all of which simulate spatial audio for headphones. It'll simulate a 5.1 (and 7.1?) setup through the headphones. Some games have spatial audio simulation built-in as well, such as Elite Dangerous. I believe UE5 also has a spatial audio engine. Finally, I believe PlayStation emphasized spatial audio for the PS5, but I don't really know the details of that.

I think it only works/is a lot easier with head/earphones? Since you know exactly where the ears are w.r.t. the speakers in that case.

Not that that's really an explanation - if that was the best sound and it was available on Blu-rays and streaming platforms, and legacy 5.1 content upmixed nicely, then yeah why wouldn't I use headphones even at home in front of the television. Less obvious for joint/family viewing I suppose.

Binaural audio starts to really fall apart when you don't have the sound exactly as the microphone setup was. Moving the speakers even a couple of feet away, and then not having them exactly lines up with your ears, it ruins the effect.

Wondered this too. That video along with the millions of ASMR videos on YouTube have very nice binaural stereo sound, but I don't see this being done anywhere else.