Those same problems still happen in Scrum and it's very hard to get out of duplication hell once the backlog gets sufficiently large. I personally think Scrum is theoretically great if done right and with smart people, but that is rarely the case.
Duplication hell is the current bane of my existence - I think we would agree that it’s more of an inter-team coordination issue than it is the type of thing that you and the four other people on your team can fix with Kanban/Scrum. But I do feel like Scrum is better at the very least at stopping this from happening because that longer ramp up time from “customer wants X” gives people a chance to say “wait so and so already did that for their turn”