"Ironically, the ruling Chinese Communist Party (CCP) will be China’s biggest obstacle in its race with America. The party’s existential fear of losing control will impel it to maintain a tight grip on the economy, making it less efficient. Giant but ossified state-owned enterprises will continue to waste resources. The CCP’s arbitrary exercise of power—as exemplified by its sweeping crackdown on China’s most successful tech companies, such as Didi and Alibaba—will stifle the innovation and growth of its tech sector more effectively than America’s sanctions."

Doesn't say anything about growth, but does imply the govt structure is inefficient, which doesn't make sense to me. It's certainly MORE efficient.

"China should be able to narrow the gap with America in the 2020s, but its growth will probably slow down in the 2030s, and the prospect of China overtaking America will look increasingly dim. If this is the case, the coming decade might be the most volatile because China’s continuing ascent might make its leaders more reckless and Washington less secure."

Yeah, it doesnt say anything like: "China will eventually stop growing because it's not a liberal democracy". There's some hand-waving that the CCP (individuals) will be reckless...which is a random claim.

Yes it does. It does it by handwaving relative weakeness without proof or argument by asserting the superiority of "our system", which is liberal democracy.