I hadn’t even thought about preferences for photorealism being a streamlining thing, but it does fit the idea.
I think it’s also a risk aversion thing as well. Few people will complain about a game looking realistic, so it’s very low risk from the point of view of publishers/investors/marketing. Most people will prefer a unique and stylized look that meshes with the game, but investors and marketing teams can’t be sure in any given case, so it’s written off as a risk.
Personally I’ve never been a huge fan of JRPGs, Some I’ve enjoyed, but rarely will I ever play them twice.
Also I think there’s a fair argument to be made that if you cannot play a role, if there are no choices to be made on how you play it, it’s not really a role playing game. It’s action adventure if it’s a linear story with only one way to play it.