These are difficult question because we are speculating about future mathematics / physics. First of all, there's the question of how much of the quantum framework will survive the unification with gravity. Up until now, all theories that worked inside it have failed; worse, they have introduced black-hole paradoxes: most notably, thunderbolts and the firewall problem. I'm totally in the dark if a future unification will require a modification of the fundamental mathematical structure of QM. Say, if ER = EPR, and entanglement can be explained with a modified geometry of space-time, does it mean that superposition is also a geometrical phoenomenon that doesn't require multiple worlds? I don't really know. But more on the point, I think (hope?) that future explorations of the quantum framework will yield an expanded landscape, where interpretations will be seen as the surface phoenomenon of something deeper: for example, something akin to what happens in classical mechanics with the Hamiltonian / Lagrangian formulations. On a side note, I've read only the Wikipedia article on QBism and my impression was that it had an epistemological leaning, not ontological: if you use only SIC-POVMs, you can explain all quantum quirks with the epistemology of probability distributions. I might be very wrong, though.