I don't think it's still a thing now because it won't be practical anymore given that elevators are fast now. Maybe there will be elevator music but only in high-end establishments like hotels and the like.
Elevator music would be great for buildings with high floors since I've experienced how awkward it could be to stand and watch the floor number change. Getting my phone doesn't come to mind because I wouldn't want to miss my floor.
Don't think I've heard actual elevator music. Agree that its disappearance might have something to do with modern elevators' faster speeds. I could see TikTok-like song clips playing between floors.