Where exactly is that storability not needed? In the VLS cells of USN warships? In the missile canisters of field-mobile SAM batteries being driven cross-country (which, for survivability on the modern battlefield need to be moving a lot more)?

The only real cases a non-storable SAM/ABM is viable are where the target being protected is so small and so known that (1) all missile infrastructure on/near the target is vulnerable and (2) sufficient advance warning is available to handle liquid fuels as needed. There is really only one case of this: Guam. I think there is a case that a dedicated unique-to-Guam liquid-fueled SAM/ABM farm would go a long way to addressing stockpile and magazine depth concerns.