Subman, sadly it seems the US navy is not as rational as in your days.
If it were, the whole LCS program would've either looked different or would simply have been a new generation FFG.
Even in the US, it is not unheard of not to realize the full potential of a weapons system. AFAIK the LAMPS program originally intended to arm the SH-2 Seasprite with Sparrow missiles to extend SAM coverage. The system worked, but was never taken over operationally. And that was in the cold war days with a lot more funds to go around. So it wouldn't suprise me if only the modules urgently needed will be purchased, most likely Special Forces, mine countermeasures and maybe ASW. The others might just be put on back burner and eventually be forgotten.
Also I doubt there will be enough modules to really have an option for each LCS. That would mean 3-4 Modules per ship, but I suppose given the cost it is more realistic to assume one module per LCS, so that we will have a de facto specialized ship with no flexibility at all.
A similar phenomenon is with the StanFlex ships of the danish navy. These might have been the inspiration for the LCS, but these are conventional warships. In theory, you have a large patrol vessel with a 76mm gun and helos that can be turned into a fully fledged FFG in very short time. Problem is, that has never been done in 10 years of service and most modules apparently are not even available.
Re german arms procurement, the opposite is true. The german military tries to become self sufficient or european equipped in pretty much everything. I think the Standard missiles for the F 124 class frigates might have been the last actual weapons bought in the US. US systems today are only bought when a comparable german or european system is not available and the weapon/vehicle is urgently needed. For example Global Hawk and Predator UAVs and .50 cal Barrett sniper rifles.
But even those systems are largely license build in germany.
But regarding the LCS program, the problem is that the US navy has largely privatized its procurement and development. That is, they basically threw away 100+ years of institutionalized knowledge in warship building and combat experience and replaced it with fancy powerpoint presenations.
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