I know this is conventional wisdom and also is very true.
however, the funny thing is, when eventually a film maker comes along and makes a film that is both new, unique, and outlandishly successful, then suddenly its "obvious" and Hollywood starts to copy that, but it takes forever for the right person to be in the right place for that to get moved forward, so you end up with rinse wash repeat stuff for the longest time.
For example, HBO taking a risk on Game Of Thrones or the initial conception of the new Marvel movies (I'm talking about Iron Man, the first one from 2007, and so on, when it was still novel), Breaking Bad was novel when it came out too. Same with The Walking Dead (the plot elements, not so much the idea of a zombie horror)
Its so weird how this industry appears to work from the outside
What’s interesting is “good scripts” are apparently a dime a dozen (diamond dozen in the rough) all over Hollywood; if you find the original scripts for many “crappy” movies they’re moderately decent. It’s after they get massaged for public consumption that they’re often the common dreck we’ve come to expect.
What’s annoying is the studios still buy up the rights to tons of properties and then never develop anything. So you can’t even have a small studio/independent film on something like (for example) the Penny Arcade comic, because someone owns those rights and won’t sell
Hollywood you either need a guaranteed moneymaker or something the people will money can buy into. One I always found interesting was how Arrival happened because the screenwriter KEPT pitching it until he found a producer/company that was interested, then he managed to convince Denis Villeneuve to direct it and it got nominated for best picture (also think it did well in box office but I can't remember for sure anymore).
Even in season one, before all of the actors could demand huge salaries - GOT had to have been an expensive show. Limited special effects (initially), but so many characters, in so different locations. The series is still not even fully written yet!
Feels like a riskier play vs any number of fully formed fantasy settings.
Hollywood has adapted all sorts of niche comic books in the hopes that something might land.
I think one of the reasons Hollywood avoids many video game franchises that people would sort of expect them to adapt or sequel is a lingering hangover from the FMV craze of the 90s. Hollywood Producers worked hand in hand with a bunch of videogame companies, lost a ton of money in the process, and seemed to come out of that distrustful of two-way working relationships with videogame companies.
That reason seems directly relevant to GK in particular: GK2 was quite successful in Sierra terms, but still somewhat unsuccessful in Hollywood (accounting) terms and likely still on some Hollywood producer's books as an old loss.