I honestly don't believe it's a cost thing overall, but just mostly incomplete offerings.
The living room is a shared space, with a variety of roles usually.
Complete and diverse solutions are desirable.
Things that are offered in living room tech need to be versatile, expandable, long lived, well supported, compatible with older tech in places too....
If Apple are going to tackle living room solutions with their normal locked down "our way or the highway" approach, they have to offer enough things to "do it all" - which they really haven't done yet.
I actually would love to see them do a "HomeBar" speaker that has ATV guts in it and you just bring your TV and have it wirelessly sync a few HomePod 2's as rear surrounds --- that would be a good start for them. The "HomeBar" could have a wide angle (and even 2x) FaceTime camera in it also.
It could be very compelling as a wonderful "do everything" TV and sound solution.