It's not the writers that are at fault, it's the studio heads/producers that are the ones that aren't reading. And even then I wouldn't say that they're not necessarily reading so much as over-risk averse. The major movie & TV studios are not looking at creating art or putting things on screen because it's something that they desperately want to see on screen, they are looking at making money, and movies and TV shows have gotten stupidly expensive these days. Because of that, they're less inclined to take risks and instead stick to what they think is tried and true. And this has been this way for quite some time and is hardly a new phenomenon. I'm old enough to remember when disaster movies were all the rage back in the '70s and it seemed like every movie studio was cranking out disaster movie after disaster movie. Before that, you had tons of war movies about WWII, and then Westerns were all the rage and Hollywood was cranking as many cowboy movies as they could.
I'm not saying that it wouldn't be nice to have some new, original content, but it's never going to beat out your sequels, prequels, and reboots which most of Hollywood feels are safe bets. But don't forget, we did get the Expanse, a great series based on a great book series. We also got Altered Carbon, which was great until Netflix decided to play it safe with S2 and completely deviate from the book.