RFROSTIII
so little American sub models?
The earliest ones, the "letter classes" were built in smalle numbers, 5 or 10 at a time, and virtually none saw War Service.
For the "Fleet Boats" the distinctions kind of need a purist to sort out, visually (whic his why far too many of the kit makers just put different names on the box without changing the moulds at all).
Once the second Nautilus (SSN-571) gets launched, there's a whole bunch of secrecy involved and not a lot of plans are published. Also, many of the post-war boats get all kinds of modifications, which complicates just how a maker might mould them.
By the time of the HKs & Boomers, again, there's not a lot of documentation out there.
And, as noted above, there's curst littel to "model." Gettign th eparts count over a dozen, even at 1/350 is tough sledding. And not much better at even larger scale (a 1/144 SSN-688 is going to be about a meter long, and will barely want for 15-20 parts).
Which can make them fairly "plain" kits. So, not so much a building exercise. Further, they tend to be all black in service, so there's not even that much to paint on them.
That's not a lot of features for a kit maker to gamble upon to produce such a kit. Not when a 1/350 modern Destroyer can easily have more than 250 parts and need extensive painting and building of sub-assemblies.
The things which make subs quiet are being as featureless as possible. Which makes the models very simple. Near to boring in some ways.