Why a cheaper new P-3 could cost more than extra P-8s

Would a newly built P-3-style maritime patrol aircraft be a cheaper way to gain more capacity than the P-8 Poseidon?

Probably not alongside an existing P-8 fleet, because duplicate training, logistics, maintenance, and basing systems could outweigh the cheaper airframe.

The discussion distinguishes an airframe's age from the value of the sensors and mission systems carried inside it. A newly built turboprop patrol aircraft might have a lower unit price than a P-8, but it would create a second fleet beside aircraft already in service. Separate training cycles, spares, maintenance knowledge, and basing support can consume the apparent saving. The answer therefore favors buying more of the established P-8 type unless the alternative replaces it altogether. Procurement is evaluated here through total force cost rather than purchase price alone.