That's just your opinion. China has made the decision to avoid food import dependence as a issue of national security importance. China cannot depend on its national survival based on the goodwill of US-led international order and goodwill of US-navy. Even if China is 4X GDP, every nation goes through cyclical downturns in power, which would be exacerbated by foreign food dependence.
This assumes China has "equal GDP per capita as US" in order to have 4X the GDP with 4X the population.
The fundamental flaw behind this assumption is that the world does not have enough resources for 1.4 billion Chinese consumer habits to match American consumer habits to achieve the same/equal GDP per capita levels. China cannot achieve $80K per capita with 1.4 billion people because there isn't enough resources on earth for 4X more US consumerism. 92% of American household has a car, with average of 1.9 cars per household. Can you imagine 1 billion cars in China? The roads would collapse with permanent traffic. The earth cannot sustain an additional 10 Billion tons of CO2 emissions annually by China to achieve the same Per Capita GDP, without irreversible global warming.
So in summary, 1.4 billion people cannot achieve $80K GDP per capita because earth cannot sustain 4X more US consumerism, CO2 emissions, and resource use. The premise that 4X GDP = 4X power is based on a fundamentally flawed assumption, not even touching that population does not linearly scale 1:1 with GDP size. Smaller countries tend to have higher GDP per capita in general too.
This is where you are wrong. I also discussed this in another thread recently. This notion that world cannot sustain US and China having the same GDP per capita is based on a flawed assumption that GDP per capita can only go up. It can also come down.
The main reason behind US high GDP per capita is its high tech dominance. Its dominant in industries such as software, internet services, biotech, aerospace. This is the basis of the all the high salaried engineer jobs in the US. Without those jobs, what will happen to US GDP per capita? It will crash down.
China is developing its industry in all of these sectors. Every sector where the west is dominant is under threat of current or future Chinese competion. Once China replaces western products and software in its own borders, it will start exporting these to the outside world.
With Chinese lower cost of living and hard working 996 culture, its inevitable that they will take away market share from the US and western countries in all those high tech fields. Once that happens, Chinese GDP per capita will go up and US GDP per capita will go down, therefore closing the gap.
You have another flawed assumption about world's resources. Resources in this world maybe fixed, but there is no rule that only the US can buy those resources. As China gets richer, it will bid higher and higher prices for those resources. US will be forced to consume less and less and China will be taking away more of the resource share. In the end, we will have resource consumption equality between US and China.
There is no guarantee that 80K dollars will buy the same amount of resources and comfort in the future that it does now. The more China and other developing countries develop, they will demand those same resources and the prices of those resources will rise significantly. This will cause a reduction in standard of living in rich countries like US and Europe.
The key to prosperity and comfortable living is money, and the key to money is strong industrial power. China is gaining both. Moreover, the world is moving from resource consumption inequality to equality. This will have catastrophic effect on US standard of living in the future.