There's no theoretical reason a political region should develop slower if the population is larger, if anything economic theory suggests the opposite (a common argument for why America's GDP is higher than Europe's is that it has a larger homogenous internal market). So China's size can't be used as an excuse for its slower development.
That's not true. You can see the historical growth rates for China and Korea here: https://data.worldbank.org/indicator/NY.GDP.MKTP.KD.ZG?end=2... . China's growth rate at no point in time was greater than Korea's was in the 1970s and 1980s.
Are we looking at the same graph?
Sorry, what does relevance geographic proximity have to economic growth? The point is that those countries all have similar cultural and racial backgrounds to China, yet developed much faster.
That's not what's going on ITT. China has had a different modernization experience from the other nations discussed above, which is entirely understandable given their very different histories, assets, infrastructures, populations, demographics, educations, etc. Your racism is that you ignore all those obvious differences in favor of one trivial, contingent aspect in which to an ineducable white American they might seem similar.
However, you could still learn something. When you compare two different groups of people, be sure to have something besides "they have the same skin color" to say when someone asks the obvious follow-up question.
They haven’t gone faster because a country like Singapore can buy enough industrial output from Japan or the US to bootstrap their industry. Nobody has enough spare capacity to build at the scale of China, so the Chinese had to cultivate industry over a period of decades. Given that most of the worlds manufacturing is done there now, I’d say they’ve been quite successful.