It would be decentralized if the same things were being built in different places. The way US government manufacturing is set up is more like taking all your organs out, sticking each of them in a separate room, and piping the blood back and forth. Every item has a mile-long supply chain and attacking any part of it shuts the whole thing down.

Decentralization doesn't matter at all if you still have single points of failure everywhere.

sorry, but the European defence is more decentralised.