Its not a problem of not having 5.1 or 7.1 or w/e, or it least, it really doesn't seem to be in most cases I've experiences this.

Stereo, 2.1, 5.1, 7.1, whatever your setup is, around about 4 or 5 years ago, a whole bunch of movies and shows basically just... decided to do a terrible job of equalizing audio levels.

My guess is that this is partially due to laziness, partially due to 'everyone just has a smartTV with automatic audio equalizers now, right?'

Probably the most famous and worst/best example of this is the first of the new Dune movies.

Half or more than half the scenes with dialogue... you just actually cannot hear the dialogue over the background ambient noise or soundtrack, and you need subtitles... but then in action scenes, shit is so loud it shakes your windows.

Maybe in that case it was something like: we only mastered this for actual in movie theatre sound environments, and just hastily flattened that and put it on streaming sites and other formats as well?

But yeah, this problem has been getting more widespread and worse over the years, and it often is not solved by upgrading to a sound system with more channels.