For the USA it would of been logistically absurd for them to try invading China, they failed to even subdue Vietnam which could of served as a foothold if they did. Likewise, China at the time simply didn’t have the naval assets to challenge the USA’s established positions in the Pacific.
Yeah at this point the hypersonic missile debacle is becoming a genuine threat to the US’s military reputation. When others see a small isolated country they have spent so much time ridiculing getting ahead of the US in an area as critical as hypersonic missiles, lightbulbs are going to start appearing over people’s heads.