There is a view, which I share, that SSKs are better suited to operations in the littoral environment particularly in constrained waters. Modern SSKs are very different from the previous generations of slow boats with limited non-diesel endurance. My interpretation of Jordan Spector's thesis is that they are a much cheaper way to supplement the SSNs in roles that don't need their expensive capabilities.
Which has a relevancy in the Baltic, Mediterranean, Gulf and even the SCS - but for the USA?
Unless based in Europe, a friendly Gulf state or somewhere such as Singapore the transit time/endurance makes them impractical, whether from the USA, Pearl or Australia - hence why Australia is now buying AUKUS.
These is no littoral waters threat in US coastal which would require a conventional sub - better handled by surface or P-8A assets; and if you start looking at northern waters and under the icecap, you are back to the SSN being a better platform.