Summer blockbuster season--survival of the tritest

Recently, I had the opportunity to see an incredible film about a woman who is a true American hero.  I am speaking, of course, about the biopic Megan Leavey. 
If you haven't seen this movie, I suggest you do.  Like right now.  It probably won't be in theaters much longer.  It opened eighth at the box office, despite an 82% rating on Rotten Tomatoes.  One week after opening, it's down to a single screening per day.  The theater had less than 20 people in it.  But what do you expect for a film that was barely promoted and nobody's even heard about?  (I wouldn't have seen it either, but Thing 1 loves dogs.  And since the story was about a Marine and her bomb-sniffing dog--it was kind of required viewing.)
Why do certain movies end up in theaters for ages and others fade out or never even make it?  Why was a film based on the Roald Dahl classic The BFG only in theaters for a few weeks while Boss Baby lasts for months?  Why did the recent release of The Little Prince, an English dub of a French film based on the Saint Exupery story (one of my favorites, incidentally) not even make it to theaters at all?  One week before it was to open, Paramount pulled it, and sent it straight to Netflix.
My guess is we live in the land of the focus group.  Movie companies, competing with streaming services in a pinched economy (going to the movies for a family of four can easily cost $100 between tickets and concessions) will only put their marketing and distribution efforts into films with massive returns.  And right now, that seems to be mostly in big-budget action movies based on the interests of Gen-X and early Millennial males.  Transformers.  Fast and Furious car chase films.  DC and Marvel superheroes (not my brand of geekery, to be honest.)  Most of the previews and theater screens seem to betaken up with some variation on one of these themes. 
But at least there is some hope.  I eagerly anticipated the release of The Great Gilly Hopkins, a film that should have made it (cast included Kathy Bates, Glenn Close, Octavia Spencer and Julia Stiles--not exactly names to sneeze at.)  Other than a few sneak previews, the movie never saw the theaters.  However, to my delight, it turned up on Netflix.  So did The Little Prince.  So will a hundred other films you never heard of or paid much attention to when they were in theaters, but start to look better after you binge-watched the newest season of Orange is the New Black and are wondering what else is on.