That pretty much sums it up. I wouldn't even be surprised if the percentage of households with anything over 2.0 has dropped in the past two decades.
Of those people with an external receiver, a significant percentage will deliberately have a stereo setup, often used for listening to music. Good speakers, but no surround sound.
I used to watch movies on an absurdly excessive 3000-watt sound system, equipped with dual 18" subwoofers... but I never bothered to get a surround decoder.
Of those people with an external receiver, a significant percentage will deliberately have a stereo setup, often used for listening to music. Good speakers, but no surround sound.