How is it ideal for 99% of folks? I'm guessing the number of people who use more than just an Apple TV with their television is far greater than 1%. In which case, a HomePod isn't ideal by default since you can't use it with your PS4, Xbox, cable TV, etc. Then of course there's also the widely reported phenomenon of video-related audio being quiet on HomePods and the common issue of having to reconnect the HomePods to the ATV. Like I said, the HomePod was obviously never designed around a home theater use case, even though it's technically possible to use it that way with AirPlay.
From your very own situation, it should be obvious that nothing precludes someone from having a home theater setup and one of more HomePods. I've got 5.1.2 in the living room and 2.0 in the bedroom, both setups connected to ATV 4Ks. With AirPlay 2, I could have music playing in both places along with one or more HomePods placed in/moved to another room for those 'special occasions'. And as it relates to the article, since HomePods aren't Atmos or even surround sound capable, they may not even get the increased streaming bitrate. Depends if Netflix just sees an ATV and says 'ok, this is capable of 5.1, so we'll stream the higher bitrate audio, even if it's only outputting stereo'.