The problem is that a lot of content today is mixed so that effects like explosions and gunshots are LOUD, whispers are quiet, and dialog is normal.
It only works if you're watching in a room that's acoustically quiet, like a professional recording studio. Once your heater / air conditioner or other appliance turns on, it drowns out everything but the loudest parts of the mix.
Otherwise, the problem is that you probably don't want to listen to ear-splitting gunshots and explosions, then turn it down to a normal volume, only to make the dialog and whispers unintelligible. I hit this problem a lot watching TV after the kids go to bed.
Yes, seems like both audio and video are following a High Dynamic Range trend.
As much as I enjoy deafeningly bright explosions in the movie theater, it's almost never appropriate in the casual living room.
I recently bought a new TV, Bravia 8ii, which was supposedly not bright enough according to reviewers. In it's professional setting, it's way to bright at night, and being an OLED watching HDR content the difference between the brightest and darkest is simply too much, and there seems to be no way to turn it down without compromising the whole brightness curve.
The sound mixing does seem to have gotten much worse over time.
But also, people in old movies often enunciated very clearly as a stylistic choice. The Transatlantic accent—sounds a bit unnatural but you can follow the plot.
Lots of the early actors were highly experienced at live stage acting (without microphones) and radio (with only microphone) before they got into video.
Yes, I forgot to mention that by "old movies" I mean things like Back to the Future. After a lifetime of watching it dubbed, I watched it with the original audio around a year ago, and I was surprised how clear the dialogues are compared to modern movies.
To be fair, the diction in modern movies is different than the diction in all other examples you mentioned. YouTube and live TV is very articulate, and old movies are theater-like in style.
That's interesting. I have heard many people complaining about the sound mix in modern Spanish productions, but I never have problems understanding them. Shows from LATAM are another topic though, some accents are really difficult for us.
I "upgraded" from a 10 year old 1080p Vizio to a 4K LG and the sound is the worst part of the experience. It was very basic and consistent with our old TV but now it's all over the place. It's now a mangled mess of audio that's hard to understand.
I had the same issue, turn on the enhanced dialogue option. This makes the EQ not muffle the voices and have them almost legible. I say almost because modern mixing assume a center channel for voices that no TV have.
Then I noticed that native speakers also complain.
Then I started to watch YouTube channels, live TV and old movies, and I found out I could understand almost everything! (depending on the dialect)
When even native speakers can't properly enjoy modern movies and TV shows, you know that something is very wrong...