If the political system in China collapses everyone should worry. That would likely result in a global economic crash the likes of which the world has never seen.
Having not studied economics/politics during my time in college, wow does one qualify "collapse" here? What are the properties?
Such a collapse would bring China back to the 1980s, increase poverty by hundreds of millions of people, disrupt global supply Chains (50% of the global electronics are shipped from the Pearl River Delta, 50% of all ACs and fridges are made there, Daimler, BMW and GM source 20-30% of their parts from China).
Western factories would reduce production as parts are missing. Western companies that export to China would have to reduce output (Volkswagen, GM would have to cut production by 30-40%, Airbus and Boeing by 20-30%). Western stock markets plummet, housing crises emerge, poverty surges, unemployment increases dramatically.
All in all, this would not be a great thing and a lose-lose situation. The Soviet Union was not integrated into the global value chains. China is. A collapse would make the 2008 crisis look like a cute little girl on a pink bicycle and bring the global economies back into the 1990s.