Why better commanders cannot erase industrial limits

Would swapping Allied and Axis naval commanders radically change the length of World War II?

Not by itself. Infrastructure, construction, and the forces already available impose limits that leadership cannot simply wish away.

Wars are fought with the ships physically in commission or in dock, and battles with the subset present at that place and time. The Royal Navy's expectation of peak danger in 1942-44 shows how assumptions shape construction: an earlier accepted 1939 deadline would likely have accelerated mass escort and carrier production from 1936.