Why delaying war would not complete Plan Z

Could Germany have completed Plan Z if war waited until 1948?

No; inadequate money and maritime infrastructure would still prevent completion.

The Plan Z bottleneck was not simply time or political will. Germany was willing to fund impressive ships but not the docks, yards, production plant, and other critical infrastructure needed to build and sustain them at the proposed rate. Extending the prewar calendar to 1948 would not make those material constraints disappear. Plan Z was therefore a paper ship list without the less visible capacity needed to make its procurement program executable.