Australia's lost option was continuous Collins production

Why could Australia not simply buy a new long-range conventional submarine matching its needs?

The requirement was unusually specialized; only continuous low-rate Collins evolution could have kept a bespoke long-range SSK affordable.

The Australian requirement was too specialized to buy cheaply from another navy's production line. Its submarines need exceptional range and endurance for a geography unlike the shorter patrol areas that shape most European SSKs. One boat every few years, developed through successive Collins flights, could have preserved designers, yards, crews, and an affordable path to incremental improvement. Once that continuity ended, recreating a bespoke long-range conventional design became prohibitively expensive and available investment shifted toward SSNs.