Why modern warships remain bespoke rather than production-line products

Is modern warship design and construction organized as a production line or as bespoke shipbuilding?

It is still mostly bespoke; fleets need class sizes in the double digits before production-line effects become substantial.

Contemporary warships remain largely bespoke because navies buy too few hulls for a sustained production line. The Type 45 program produced six ships, while the Royal Navy's Type 26 program discussed here reaches only nine. Double-digit class size is the point where repeated construction begins to resemble series production. Single-digit programs retain too much one-off engineering, learning, and supplier effort to behave like mass manufacture.