Once agreed parameters produce an acceptable design, further additions can be reserved for a later batch. Repeatedly asking what else a frigate could do prevents that closure. One proposed explanation is that companies gain opportunities to increase contract value while governments postpone construction, crewing and maintenance expenditure. Navies retain a theoretical answer to whatever new mission arises. Those incentives can sustain an adaptable proposal long after a definite, buildable ship is needed.
Notable Point · 1:53:38-1:55:54
Why requirements creep persists after a design should close
Competing incentives can keep frigate requirements open even after the agreed design should be ready to build.