Actually, I have another thought that I "prefer" THAAD to stay in SK for a period long enough for China to use as an excuse to displace and weaken SK's key business, namely Electronics and Cars.
This would sound selfish, but from a long term economy stand point, China is climbing the value chain ladder. A decade or two ago, China and SK are compatible where China makes low end product while SK makes the mid and high end. Today, China is moving to the mid and high, Chinese companies need market shares that and the first and biggest is Chinese domestic markets. The easiest targets to displace are SKs, natural targets. Although Samsung home electronics are among the top on par with Japan, but Chinese companies have been eroding that market for years, mobile phone and TV are good examples.
Overtly displacing SK companies would be against WTO rules, but undeclared political sanctions out of national security concern would shut everyone up. I would thank SK leaders for handing over their market shares to China. Hehe talking about shooting one's own feet.