Probably not for 'power' (does that work?) users, but for people like my mom they're pretty much already gone. They started disappearing for her when iTunes was dumping her music into a directory and she had no idea, to her it was indistinguishable from how Spotify works, so now that everything streams like magic she pays zero attention to files or the idea of files. She thinks in terms of galleries, not image files. If I open some sort of file explorer in front of her, I've just gotten 'techy' on her.
A few years ago when I was doing a help desk job, the sentiment was similar. I asked a user to navigate to a directory on Windows and he stopped me. He said, "Hold it now, I'm not a computer person."
So maybe not 'go away,' but perhaps become increasingly invisible and especially so to average users.
iCloud backs up your entire phone. Most apps store stuff remotely on their servers. And even in the case of photos various services will sync those off your phone as well.