I can see where you're coming from (that bigness is an issue, regardless of whatever role China may play), however I do think the China example helps better concretely illustrate some of the author's points.

In particular, 'bigness' alone reduces innovation and can cause misaligned incentives. However, 'bigness' in addition to an outsourced supply chain means the misaligned incentives are allowed to be that much stronger -- now, not only is the US economy less innovative than it otherwise would be, it has also enabled a feedback loop that would not necessarily act in its best interests.

Does said entity necessary need to be a foreign country or even a foreign entity? No. However, as "the entity that has captured critical components relevant to the US manufacturing supply chain", China is a nice example of an "entity with bigness" and one with some explicit misaligned incentives (at least, in terms of certain cultural values), so it illustrates the point more directly than some other examples.