I can think of only a handful of targets that the US might want to shoot at. (I realize there might be a ton, and this is my lack of imagination). The handful I can think of, almost all of them seem like they're in the supply chain to actually build the torpedos. I'm pretty skeptical of the depth of the US stockpile.
To put it another way, if there was a war so bad, the US reinstituted the draft, would these tools still be relevant? The US industrial base is mighty, and could certainly retool to meet whatever need arises, but that'll take years.
Really seems neat, but after you've taken your 20 or 50 or whatever shots, how do you resupply? Seems like you'd need special coatings or shelf stable chemicals or a hundred other things to make the super fancy weapon.
it sure _seems_ like (although I have no fucking clue, so I'm asking) the super fancy weapons are available for a few weeks if things get real bad.
_edit_ realized I didn't actually ask a question. Can the US actually build these things from, like, minerals? It's a big country, we have them. The industrial base doesn't seem tuned for actually doing that though.
_further edit_ I'm a very silly person. it seems like the only must have is a plausible second strike capability. It's great to be able to protect the free flow of oil, or defend the Kurds from chemical weapons. Hell, one of the most American things I can think of is protecting yankee clippers for safe trade. It's part of the Marine's Hymn. but clearing pirates from the shores of Tripoli isn't absolutely vital. I'd sort of thought that subs jobs in the modern world was making sure that if the US can't play, no one else can either, with moderately sized nuclear weapons. Again, I'm a very silly person. The question with the further edit is, do subs have an essential job beyond second strike cabability?