I think the problem is head related transfer functions are too specific to people's head size. One time in my life I have heard amazing HRTF encoded audio with

I think the problem is head related transfer functions are too specific to people's head size. One time in my life I have heard amazing HRTF encoded audio with this dog running from what sounded like 100 feet away and then coming up and sniffing my ear. It was freaky. That was the only time the transfer function fit for me. Every other time it just didn't work and just sounded like the sound panning around the standard stereo field. If HRTF was one size fits all we would be long done with all this but I don't know that there is a better option that can be done for a reasonable price for what you get.