Having lived in China for seven years I see no sign that the Chinese have eaten, are eating, or are going to eat America’s lunch. Growth at the technological frontier is about what the best are doing and diffuses from there. I am unaware of any academic field or major industry where the US is not in the top three, hardly surprising given its 5% of global population and 25% of global economic activity. As long as the US has enough strivers and hard workers it can afford plenty of slackers.
The only way for the US’ relative position not to decline with China’s rise involve megadeaths, just as after WWII it’s relative power could only decline.