For those struggling with dialogue and trying to avoid subtitles (I'd watch everything with subtitles if I could, cause I'm bad at understanding speech, but DP hates them so I do without), there are occasionally some things you can do to improve audibility:
On Amazon Prime, some programmes have a setting called something like "Dialogue Boost" in the soundtrack options (the same menu you would go to to switch from hearing English to hearing a French dub, or to switch to an audio-described track for blind viewers). Where that's an option, it's worth trying. I don't know if any other streaming services have something similar, though.
Another option that used to be helpful sometimes, but isn't so much any more, is that if you have a surround sound system, turning up only the centre speaker might help to disproportionately increase the volume of speech over background noise.
If you have equaliser settings, it can sometimes help to future with those, too, though not much TBH.
I agree that some of the dialogue audibility problems are for technical reasons to do with the difficulty of mixing soundtracks for a vast range of different audio setups. But some of the problems are, I think, down to the fashion for ever-greater appearance of realism/naturalism.
They got the idea that always having actors with faces visible, clearly enunciating all their lines, and saying sentences that always make perfect sense so that the context will help you with anything you might've missed, wasn't very naturalistic (true), and dramas might therefore be more realistic, immersive, and overall better if every second or third line was garbled nonsense mumbled into a pillow three miles away.
In the dark.