This is not a disadvantage for all MSRs. Only breeders need chemical plant. Not fair to compare a solid-fuel burner to liquid-fuel breeder.

Let us compare liquid fuel breeder vs. solid-fuel breeder: Reprocessing solid-fuel involves more complex chemical plant with physical mechanisms to declad and convert solid-fuel to a processable liquid. Fabricate processed liquid to solid-fuel and put it back in the reactor. Solid fuel breeders have additional physical and chemical processes/steps.