The price difference easy to explain :The exorbitant prices that people in China pay for common meats like beef and pork are absolutely intolerable compared to how easily affordable they are to the average American. When the average blue collar Chinese worker can use the wages that he earned in an hour to buy his family a kilogram of whole cut fresh beef (not ground up fat bits or crap like that), then living in the West will lose its allure to the Chinese people.
China has LESS arable land as the USA or Russia, and the USA had in the 80s 50% more than China now.
Considering that one kg of meat require ten kg of grain there is little chance to see the meat prices going down much in China.
The biggest jump for the agricultural productivity is the nitrogen fertilizers,
It shown 50% increase since 2000, and the level of use peaked, so the best part of productivity gain exhausted.
With fertilizer the per hectare productivity could be doubled , anything else showing only marginal improvement.
(remark: best part of the Chinese natural gas import is for fertilizer manufacturing, and the biggest reason of the NK famine was the lack of oil for the Haber process to make fertilizer. One of the fist plant to converted to coal gasification was the NH3 plant in Anju)
Best strategy for China should be to increase the food import from Russia, from the new permafrost free areas. But even with that the food supply would be way less than for the average Russian .