Right now, the major barriers keeping China's capital in China are actually chinese regulation and china's economic growth in that order. China has very strict capital regulation on how money can be moved around across borders. Also, so far, the Chinese govt. has only been interested in holding on to US treasuries so that capital is effectively out of circulation. Lastly, even if some chinese citizen is allowed to invest in foreign infrastructure, why would they when the chinese infrastructure is experiencing faster growth?
Still, once these regulations prove too onerous to maintain (which they will) and once China's economy stabilizes, we will suddenly find that half the US is owned by China and that will cause the labor markets to shift again possibly moving production back to the US and away from China. Still, thats ~20-30 years away and who knows what else might happen in that time.