I think there's a threshold fedi would hit and we'd start seeing these duplicates diminish. Not all of them will go away, that's always going to be a part of a federated network of servers each with their own user base. But some big ones will come to dominate and naturally acquire most or all of the available audience. You can't federate human behavior, but this system does allow for much better migration and diversity between groups than a singular aggregate like reddit. We don't need to make news and TrueNews. There's no monopoly on such terms. You can just make your own news somewhere and promote it and run it your way.
But right now, this place is in an embryonic stage. Cells are forming, dividing, dying, and being born. I would expect the landscape of it to change given enough freedom to grow. The more users we acquire, the more these magazines will evolve and change to accommodate. I expect some of these duplicates are going to go their own way or die off or be replaced. It's gonna be interesting to see how it shakes out.