The thing that makes pre-rendered backgrounds so great are the kino angles. Brainlets who says that you can have this fidelity in-game now don't even get it. First of all, no you can't, and even if you could it's never gonna be the same because you can make each new pre-rendered screen look unique and distinct from other on a fundamental, handcrafted level whereas in-game everything runs on the same engine and will always adhere to the same restricted conditions, same lighting etc.
But more importantly, people who say 'look, this modern whatever has just as much clutter now!" are missing the point, you can literally never have the same atmosphere with your generic free moving-camera behind character, you can never instill the same level of emotion when you're always seeing everything from the same flat eye-level, one singular perspective.