The simple fact is that most people don't really care about sound quality and the 'good enough' sound they get out of TV speakers or a soundbar is plenty.
'Proper' Surround speakers - as in ceiling mounted speakers in a dedicated home theater room with acoustic treatment, as opposed to a soundbar with an atmos badge attached - have always been expensive and cumbersome and have only grown even more so with the proliferation of fancy new formats like ATMOS and DTS:X. Of course, part of the reason they are so expensive is because of price fixing by AVR companies like Denon, making an already niche market even smaller by erecting a taller barrier of entry. When companies have to resort to underhanded tactics to prop up their margins rather than creating compelling products that people want to buy it is a pretty good sign that the industry is in dire straights.