It's all a system of tradeoffs. America is pretty much fully post-industrial; our WWII and postwar industrial miracle already happened. The standard of living increased and now you have to pay cement mixers and steelworkers more, they want hazard pay and can take private contracts. China's still coming down off this curve, and depending on state policy they might keep stepping on the gas. That too can limit your ability to modernize, depending on where you see the country going.

It is somewhat reminiscent of the old Soviet anecdotes where per-unit costs for RPGs and AKs were reaching staggering lows in the 70s and 80s. Not because there was necessarily a high demand for man portable anti-tank rockets and modern rifles, but because the factories were ordered to produce them in increased volume year-over-year. The resulting surplus was largely stored in Ukraine, sold to Russia's enemies after the Cold War, and crashed the price of USSR-era infantry weapons. The overzealous industrialization of the military cost them huge amounts of materials and labor, held them back from future modernization, and even helped arm Russia's enemies.

Being able to do something remarkably cheap at a giant scale often requires sacrifices. Right now, China and India are deriving remarkable value out of their trades laborers. Eventually they too will want to modernize though, and if there isn't enough natural demand for their high-margin finance/services sector then it could risk another "great leap forward" situation. This is the delicate transition America managed to pull off, despite it's failures (and marked shortcomings nowadays).