I don't think that's true. In fact movie producers are notorious for "phoning in" the 5.1 mixes for the streaming platforms, focusing most of their energy on the theatre mix with Dolby atmos and what not. Usually the 5.1 mix you get on netflix is hurriedly put together as an afterthought.
That would be plausible except I miss much of the dialog in theaters, too.
I am not a 20-something, but I always turn on subtitles. I never could make out most of song lyrics, either, with some exceptions. Most usually, only the chorus.
That's basically the same point though - it's not that special attention is given to specifically 5.1, it's that a) more separate speakers helps in itself; b) it's primarily mixed for such a multi-separate-speaker system.
I have a 5.0 system, and the dynamic range mumble voice + super loud explosion is still very present, even when I artificially boost the center channel. I think voices are actually better on a typical tv speaker 2.0 setup.
The only fix I found was to rip all tracks, apply normalization + compression filters to the audio tracks in Audacity, finally to repackage everything as MKV.
