Classic schooled actors with theater experience are being replaced by young actors using basic conversational speech and volume. More natural but not that easy to understand.
No, there's definitely an element of not speaking clearly.
Matthew McConaughey and Tom Hardy as examples. Chris Nolan gets shit on for his terrible sound mixing, but him picking actors who mumble is the main issue.
Put on a movie from 1980 vs one from 2020. The voice clarity is night and day.
Atmos won't save you from shitty sound mixes, I have a pretty nice speaker setup and still have to turn on captions if I want to hear a conversation without my neighbors calling the cops during the next action sequence.
Not just that, they assume you have an IMAX Dolby system installed in your theater sized living room, that everyone obviously has. Bad mixes are inexcusable and sound mixing snobbism is a symptom of the pompous pretentiousness that is the rotten core of Hollywood. Yes, Hollywood, most foreign films with DTS have perfectly good and serviceable mixes that sound nice in both Stereo and Surround..