China arguably is a global power today. I think what Ai Weiwei means is if China can be a long-lasting empire like the Roman or the British Empire.
Also, this reminds me of the classic Upton Sinclair quote: "It is difficult to get a man to understand something, when his salary depends on his not understanding it." The man being Weiwei in this case.
All of this was true of the USSR and yet it was a global super-power for half a century.
Classical composers as you mentioned, literature (Russian realism), opera & ballet. Russian academies in those areas are still considered the best in the world.
When England was a world power, they weren’t exactly known for human rights and yet they lead the Industrial Revolution.
Even in Jim Crow America, there was still a lot of creativity from those that were oppressed.
“Can China be a global power? I don’t think so. It can gain an advantage, that’s true. But it doesn’t have soul. It doesn’t have heart. It doesn’t trust its own people. So it has no self-identity in the sense that it has never accepted human rights as common values. No freedom of speech, no independent judicial system. If those don’t exist, how can you have creativity? How can you be a country? So forget about China. China is an illusion. It’s there, it’s large. But nobody can tell you what it is.”
We live so much with representational democracy - so close to it - that we take it entirely for granted. We imagine that our situation would be somehow replicable with other forms of government. That we could have a benign autocracy and everything could be the same. People talk about China as if they're just a slightly different version of us. But instead of a mirror or an aspiration they ought to be a warning.