I think such prophecies are greatly exaggerated, since it's rare that a developed country "gets taken over" by another country. The only cases that come to mind would Germany and Japan after WW2 and even these bounced back and took back control. And that was after WW2, so after huge disruptions.

But, getting back on track, things are different. China is 10x the size of Japan. If China's GDP per capita gets at least close to that of Japan's, they will both double the world's economy and also become 50% of it, like the US was a few decades ago. They will dwarf everyone, including the US. So there will definitely be a huge Chinese influence, world wide.

I think this entire exercise is conversational bullshit because there is no metric for 'winning'. Quality of life is relative. People prefer different things, that's why those who are able, relocate to somewhere that suits their preferences. Japan benefits greatly from being an island, not having to worry about their national security for decades and a tight immigration policy.