The word universal is misleading i think. Rather, "having the software and hardware design flexibility to include new weapons as they emerge" is a better term. In this way I think mk-41, SYLVER, mk 57, 052Ds CCL VLS are all equally universal. Now the real challenge is whether the VLS is designed with enough physical space and venting to provide larger new generation missiles to be hot launched. That is a big reason why mk-57 was developed, to accommodate newer missiles with bigger exhausts that mk-41 can't handle
The CCL VLS gets around this by having both a hot and cold launch option. The benefit of cold launch is that the booster only ignites once its driven out of the cell by a piston, meaning bigger missiles with bigger and hotter exhausts can be fitted compared with hot launch VLS with smaller exhausts
Venting is less of an issue with cold launch.
one could design a cold launch system where the gas generator is nothing but a slower burning pyro charge., after ignition the gas expands and push the missile out via a ejector base. the problem is sometimes the vls slot is not strong enough to take the pressure of ignition. one could theoritically design a sleeve for the missile such as a bullet cartridge but that takes valuable space out of VLS.
cold launch also pose issues for the missile itself. at least the Guidiance navigation and control part. where essentially missile system itself is starting not from rigid platform but from a suspended mid air position where its attitude can vary considerably. complicated but not impossible.
in the old days where the SAM are pretty dumb. it has to align itself with the direction of the beam (radio beam riders) or lined up pretty nicely with the returns on the radar illuminator (SARH). or else it would just fly into the ocean. then comes the autopilot but that requires you align the gyro and warm up the electronics nicely before let it fly.
This day and age the missile designers are spoiled. they can essentially buy ready built solid state INS systems size of a watch and get reasonable performance out them, and write everything in C++,
n the olden days you actually has to design the software via vaccum tubes!...I digress...