Much of the industry has been aggressively data-driven for so long that over generations of talent the ability (insututitionally and/or intellectually) to lead with your gut has become a lost art. This is why AAA is becoming perversely fascinated by indie. Indie doesn't have the data; must rely on gut. Sometimes you see games that are doing a very specific thing in AAA (following their gut, their heart) but it's still confined to the institutional practise of parsing it all through available data. The datasets are all increasingly trash because they can't predict breakout hits, nor predict failures. And so if you can't rely on data and you've lost the institutional 'gut instinct' that drives the furore of expression (defines a game), you get stuck. If public, panic. Become safe (which is dangerous). Hence: genres disappear, until indies create breakout hits and introduce new data: perverse attachment, etc etc. Tl;dr it's because the means to do something you want to do have shrunk because of a bunch of silly shit.