It's interesting that you're citing a film made 60 years before the 21st century as an example of a 21st century trend. If anything, we seem to be moving in the opposite direction. Star Wars tried to explain where the force comes from. Christopher Nolan includes ridiculously detailed exposition dumps explaining everything (in spite of the ambiguous ending of Inception, everything about how the world worked was explained in meticulous detail). Even the canonical mystery box master himself, Damon Lindelof, took to heart all the backlash about the non-explanation ending of Lost. Nobody expected The Leftovers would ever give an explanation of what caused the Sudden Departure, but it did.
Heck, even David Lynch himself gave Laura Palmer an origin story in Twin Peaks: The Return! And even where he tried to preserve some mystery, the companion book by Mark Frost explained all of it.
I really root for Nolan; I very much liked Interstellar and enjoyed Tenet, but I think he's a clear example of someone who excelled so much at a commercial medium that the get-the-most-butts-in-seats factor necessitates the exposition diarrhea. There's just enough ambiguity for the common pseudo-news-site or vlogger to make "the ending of $FILMTITLE REALLY explained" content.
I think Lynch, who's learned to "rule over small films than serve large corporate ones" [1], probably bent over a little bit to get The Return made, but I still left with as many, if not more, questions as I had coming in.
Heck, even David Lynch himself gave Laura Palmer an origin story in Twin Peaks: The Return! And even where he tried to preserve some mystery, the companion book by Mark Frost explained all of it.