it's very funny how when watching a movie on my macbook pro it's better for me to just use HDMI for the video to my TV but keep on using my MBP speaker for the audio, since the speakers are just much better.
Just anecdotally, I can tell speaker tech has progressed slowly. Stepping in a car from 20 years ago sound... pretty good, actually.
IMO, half the issue with audio is that stereo systems used to be a kind of status symbol, and you used to see more tower speakers or big cabinets at friends' houses. We had good speakers 20 years ago and good speakers today, but sound bars aren't good.
They do sound pretty much ok for very discreet objects compared to tower speaker. I only occasionally rant when sound skip a beat because of WiFi or other smart-assery. (Nb: of course I never ever activated the smart assistant, I use them purely as speakers).
Lower spec speakers have become good enough, and DSP has improved to the point that tiny speakers can now output mediocre/acceptable sound. The effect of this is that the midrange market is kind of gone, replaced with neat but still worse products such as soundbars (for AV use) or even portable speakers instead of hi-fi systems.
On the high end, I think amplified multi-way speakers with active crossovers are much more common now thanks to advances in Class-D amplifiers.
The time and money cost of going further than that is not going to provide a sufficient return on investment except to a very small proportion of people.
Doesn't matter if it makes vocals part of the backgroud at all times.
I don't find the source anymore but I think that I saw that it was even a kind of small conspiracy on tv streaming so that you set your speakers louder and then the advertisement time arrive you will hear them louder than your movie.
Officially it is just that they switch to a better encoding for ads (like mpeg2 to MPEG-4 for DVB) but unofficially for the money as always...
Film makers want to preserve dynamic range so they can render sounds both subtle and with a lot of punch, preserving detail, whereas ads just want to be heard as much as possible.
Ads will compress sound so it sounds uniform, colorless and as clear and loud as possible for a given volume.
It's not just that. It's obsession with "cinematic" mixing where dialogues are not only quieter that they could, to make any explosion and other effects be much louder than them, but also not enough above background effects.
This all work in cinema where you have good quality speakers playing much louder than how most people have at home.
But at home you just end up with muddled dialogue that's too quiet.