GOT got stuck in a strange feedback loop with some of its audience, they adopted some kind of cult of the badass and producing shocking or "badass" moments for social media.

First books had same shockers, but then he run out of characters to kill.

Maybe you're right that the books didn't give the tv script writers enough fodder for the shock and awe they wanted, but that just shows they were the wrong people to adapt the story for tv.

I think that after season 4, individual plots/episodes were still fine (the finale of Season 6 was fairly enjoyable). Season 8 was the exception, where it really felt like the show writers were tapping their watch and going "oh wow look at the time".