I completely understand why your average moviegoer (is there such a group of people any more?) would walk out of his movies.
When Thin Red Line came out (1998) I saw it a few times in the theaters, then Saving Private Ryan came out about the same year, and I remember having interesting debates with my friends about which one was a "better" war movie. It was this perfect A/B study. They found Thin Red Line completely boring and terrible: no main hero, one who is sort of the main character dies senselessly in the end (well he sacrificed himself, but it wasn't with any sense of bravado or anything). And my point was, that's kind how war is: there are no heroes and people die senselessly and often stupidly, and there is a lot of boredom and sitting around waiting, too.
> This kind of earnestness stood out in an age of relentless irony and snark.
That's why I like him. And to be fair, I am the first one to enjoy relentless irony and snark, but on a deeper level I realize it's also unhealthy and often is an escape from something terrible or a way of distancing from what's happening, so when something more honest and authentic some about, I pay attention.
Obligatory mention of that iconic low-angle shot of The Mother floating gracefully across the plains. One of the best of all time.