"Sin" is the wrong framing, but outsourcing most of your capability to actually make stuff can definitely cause problems for a country.

For example, on a military level, the US is concerned about how rapidly China is catching up in naval capacity, China is building new warships far faster than the US can. And it's hard not to notice that China's overall shipbuilding capacity is more than 200x higher than America's.

The US has a lot of pride over having been "the arsenal of democracy" in WW2, and it's well known that a huge part of why the US was effective in that war was sheer mass: the US simply made much more war 'stuff' than any other combatant. But if the US was to get in a shooting war with China today, it would likely be China that would enjoy an advantage in production scale, with the US trying to make do with fewer vehicles and munitions.