You’re right, I dug back into it and the specific “WWII-level destroyer production” line was me mangling a few different sources that were making related but not identical claims.

What is well documented is that China’s shipbuilding capacity and tonnage output absolutely dwarf the United States today. A 2025 CSIS study cited by Navy Times found that a single Chinese shipyard produced more commercial ship tonnage in 2024 than the entire U.S. shipbuilding industry has built since World War II, which is where I likely had the WWII comparison stuck in my head. https://www.navytimes.com/global/asia-pacific/2025/03/11/chinas-shipbuilding-dominance-a-national-security-risk-for-us-report/

That same report notes that China now produces over 50% of global shipbuilding tonnage, while the U.S. accounts for roughly 0.1%.

Separately, U.S. Congressional Research Service and Navy assessments estimate that China’s overall shipbuilding capacity measured in gross tonnage is over 200 times larger than that of the United States, largely due to its integrated civilian–military shipyard system. https://www.congress.gov/crs-product/RL33153

In terms of actual naval output, a senior U.S. Indo-Pacific Command admiral has stated that China is currently producing roughly 3–4 times more naval tonnage per year than the United States, even before accounting for its massive commercial shipbuilding sector. https://www.businessinsider.com/china-outpacing-us-shipbuilding-top-indopacom-admiral-says-2025-4

So the WWII comparison was overstated, but the underlying “issue” is arguably more serious for the US. China controls roughly half of global shipbuilding capacity, much of it in dual-use yards that can be partially redirected under wartime mobilization. The United States, by contrast, represents only a fraction of a percent of global shipbuilding and lacks the industrial depth to rapidly replace naval losses in a prolonged conflict. Apologies again I will have to avoid posting so early in the morning without rechecking my sources.