Not to mention that the Reduction Gears in most Naval Vessels are leased and not actually owned by the DOD. Very few ships in the Navy have Reduction Gear Assemblies that are Naval owned. That is because the price of such machines are very very very expensive. Back when I was in the price of one Reduction Gear Assembly was about half the cost of a Frigate I shit you not. Who knows how much they cost now.
That explains why the Navy tried to hook turbines directly to electric motors on a few subs (besides the obvious noise reduction advantages).
Streamlining procurement could be solved by just getting a lot of 3D printers and CNC machines for every base. Shipping bulk materials is simpler and cheaper than lots of small fiddly bits.
As somebody that works in a machine shop, you have
no idea how impossible this is. You will never be able to produce everything needed on base, simply due to the sheer amount of jigs/fixtures you would need to store, maintain, and replace in order to maintain production of every single random part.
And that's not even getting into the obvious problems with optimizing programs and job processes, dealing with the inevitable production difficulties as you switch between jobs, and management being fucking stupid while having absurd demands.