The Kirin 980 SoC uses the Cortex-A76 which was designed in Austin, TX, United States of America.
The statement "The U.S. still makes — or at least, designs — the best computer chips in the world" is accurate in the context of a manufacturer attempting to build a high-performance microprocessor-based device.
Exactly, thus far China doesn't have the technology to do sub-14nm foundry work at any notable scale, and as we saw with Dhyana, they apparently don't have the internal talent to improve AMD's Zen cores. The foundry issue isn't apt to change anytime soon, as newer nodes are extremely expensive and take years to bring up (see Global Foundries & Intel's troubles with newer processes).
The statement "The U.S. still makes — or at least, designs — the best computer chips in the world" is accurate in the context of a manufacturer attempting to build a high-performance microprocessor-based device.