There are doubts about the definition of exaFLOPS, whether it means nominal performance R_{Peak} or payload performance R_{Max}; measured by which benchmark (and which real-life workload). There are limits for of supercomputers’ PAYLOAD performance, simply due to the laws of nature: the speed of light (and EM waves) is finite.
https://www.researchgate.net/publication/228367369_Reevaluating_Amdahl's_law_and_Gustafson's_law
https://link.springer.com/article/10.1007/s11227-020-03210-4
Formerly,
https://www.scmp.com/tech/policy/article/3015997/china-has-decided-not-fan-flames-super-computing-rivalry-amid-us
referring to political decision. Now they simply keep secret.
Around exascale, the limits approached. Only trial and error development goes on, see for example Aurora, Gyoukou, Fugaku, SpiNNaker, etc.
Yes, there is no China exascale supercomputer. There is no US exascale supercomputer, however. Have a look at
https://www.hpcwire.com/2022/05/30/top500-exascale-is-officially-here-with-debut-of-frontier/
Their first figure shows a ramp on the right side, and a narrow step on the left side. If it would be a similar ramp at the beginning of computing (to collect and distribute data at the beginning and at the end needs the same bus system, and the same behavior), the averaged efficiency would be below 1 eFLOPS. So, they have built a 2nd specialized hidden “supercomputer” just for distributing the data at the beginning. As
https://www.nextplatform.com/2022/05/30/frontier-step-by-step-over-decades-to-exascale/
noticed:
“As configured for the Linpack run, the Frontier system had a power draw of 21.1 megawatts, but
when the Frontier machine is first set loose on the Linpack, it draws an extra 15 megawatts of power as it is starts the job.”
(driving the I/O ports needs power, and that 2nd supercomputer draws some 15 MW extra power for the firs few minutes while the visible supercomputer makes zero FLOPS.). However, if this 2nd supercomputer would be visible, with its 36 MW power consumption it would not be “green” any more.
BTW, this one-time trick work for HPL only; see its HPCG efficiency.

After more than 70 years of continuous development, New China has been able to compete with the United States as a superpower in the field of cutting-edge technology. If you insist that China has slowed down its scientific and technological progress due to so-called “political system” issues, then the United Kingdom, the United States, and a series of countries that have been constantly overtaken by China, as well as slow developing regions such as Africa and India, Their technology is indeed accelerating rapidly. The so-called century long accumulation of science and technology, which Western scholars are proud of, appears so shallow under the socialist system that there will soon be more breakthroughs in many fields. This is a fact that the US government has to admit, as they have listed China as a comprehensive competitor. China has been implementing the socialist political system for more than 70 years, perhaps this is what you call “deceleration”.

Westerners have been saying China would fail for decades with no result. Yet your own country and infrastructure is falling apart.

Decelerating science? Do you have any idea on what id actually going on with western companies flocking to China?

Compared to Americans that keep bombing 3rd world countries, China is actually doing something to improve people’s lives unlike backwards countries where poor healthcare leads to a million deaths. Guess that is the new American innovation.

Your probably pulled that outta your a$$ since the US constantly employs qualified scientists from other countries regardless of politics. This goes way back from operation paperclip. China is bound to fail as they always do, since they practice isolationism (a mix of nationalist communism) and this is mathematically bound to lead in decelerating science. Hope they open up to the world as they’re very smart people.