There is no possibility Chinese civilization could've ended up like the Native Americans. China is much too large, too populous, too entrenched. Absolutely nothing in common with sparsely populated Native tribes. You can argue there are slight parallels with the Aztecs but the Aztecs were far smaller and most died from diseases, which Chinese had immunity too.
Even Africa, which was mainly tribal and nowhere near China's level of civilization has largely managed to maintain their populational grip on the continent. Only North America, Australia and Siberia has seen the natives largely marginalized or overrun because their numbers were small to begin with and they had no entrenched urban civilizations.