Comparative advantage means countries benefit from specializing in producing goods or services where they have the lowest relative opportunity cost - not necessarily where they're the best overall. Even if China focuses on technology (and this is far from decided), America can still thrive by specializing in other areas where its relative efficiency or unique capabilities are better.

Examples: Germany specializes in high-precision manufacturing, India does well with software development, IT services, and medicines, Australia exports minerals, natural resources, and agricultural products, etc. Everybody brings something to the table. The world economy cannot possibly get worse by adding 1B people doing top-level work.

> Ricardo's theory implies that comparative advantage rather than absolute advantage is responsible for much of international trade.

https://en.wikipedia.org/wiki/Comparative_advantage

BTW these would have been great ECON 101 discussions to have before the election.