It's not safe to make garbage and expect to turn a profit.
Exactly this. There are amazing numbers of untapped novels out there that would make wonderful movies.
That the movie industry spends most of its effort ignoring this resource leaves me with absolutely no sympathy whatsoever for any whining I hear from them. Where's Neuromancer? Where's Tau Zero? Where's (any one of) the Bolo stories, or Galactic Odyssey? Pretty much anything Gene Wolfe ever wrote? Axis of Time series? Novik's Temeraire? I could on for days just in the areas of fantasy and SF. There are tons of untapped thrillers and etc. out there too; Lots of as-yet-to-be-mades (not to mention as-yet-to-be-made-wells) from Clancy, Clavell, etc.
And then, when they commit crimes against art like create utter crap like "Soylent Green" out of really good books like "Make Room, Make Room"... then I'm glad they're not digging up good novels as sources. Let 'em make more formula superhero movies like the (utterly terrible) Batman vs. Superman we're talking about here. Keeps me from tearing my hair out.
Honestly, if the movie industry died (which it shows no sign of, this buffoon's whining aside), I'd just read more books.