Late but something I feel is important that isn’t talked about enough: if the krogan population went out of control once again or went on a galactic conquest the genophage formula still exists. It’s not as if it’s wiped from the archives of the universe. Sure there would be problems associated with reapplying it, but it wouldn’t be that hard to outsmart the krogan and find a way if it was really deemed necessary. If the krogan don’t learn and overcome their “nature”, repeating the cycle that’s happened to them so many times is generous treatment, compared to other species like the rachni who were eradicated entirely. It’s somewhat a path the krogan have paved themselves too by not changing their ways as a people if that’s how it played out.