Why prewar US destroyers came in many small classes

Why did the US Navy build many small destroyer classes before the Fletcher class?

They were iterative batches that developed and preserved design capability under constrained peacetime funding.

The panel describes the sequence as batch development rather than a collection of unrelated experiments. Each class allowed the Bureau of Ships to refine designs, retain institutional knowledge, and respond to changing requirements. Political reluctance to fund escorts kept orders small and encouraged demands that every hull perform too many frontline roles. Wartime demand finally supported the large, standardized Fletcher program, but the prewar batches kept the design organization alive long enough to reach it.