Geographic benefits erodes with technology. Technology has compressed the world, global shipping gives actors with money and leverage access to resources around the world. Post war US power projection is based off the fact it has technology to reach others while others cannot reach CONUS. Which has/is going to change shortly. Now techology like precise long range strikes makes CONUS no better than Saudi. Having resource autarky =/= resource security when modern missiles can take out critical infra on CONUS. Geography matters less than ever.
As it happens, China is the same size as the US, has a lot of natural resources, and also large swaths of very fertile land (which partly explains why they have always had a large population) and, for instance, they are the largest producer of both wheat and rice in the world.
I recently heard (on some youtube video) that China has 10% of the world's farmland and 20% of the world's population.
Also, any country that is not extremely poor does mechanized farming, which has been described as "using land to turn petroleum into food", and most of the petroleum China uses comes from the Persian Gulf or even further away. (For example, I'm pretty sure that most of Russia's flow of petroleum to China comes via ports on the Black Sea and the Baltic Sea.) In contrast, (because of the fracking revolution) the US produces all the petroleum it needs domestically. If that changes in the future (for example because of a commitment to reducing carbon emissions cause regulations that discourage petroleum production in the US) then the US can probably make up any shortfall with petroleum from Canada.
And I'm pretty sure China must import most of its needs for 2 of the 3 major fertilizing commodities (nitrogen, phosphorous and potassium).
And they get a lot of grain and oilseed for example from Ukraine or at least they did until Russia stopped the flow (according to a Youtube video I recently watched).
I see a lot of statements here to the effect of how screwed the US would be if it suddenly couldn't import things from China, but very little on how much more screwed China would be if it couldn't import things from other continents. At least the US can feed its population, keep the electricity on and keep the trucks moving on its highways without imports.
Cherry picked understanding from conditions 10+ years ago.
PRC agriculture has absolute food security in terms of domestic calorie production and was net fertilizer exporter via coal gasification in 2010s but turn importer after coal crack down due to green initiatives. Coal back on menu due to recent geopolitics that prioritize energy/good security
PRC can feed herself with domestic inputs worst case scenario. With surplus if she moves to mechanical farming - current 200m farm household basically make job programs with lots of farmers pursuing cash crop instead of efficient calories.
Finally discussion on import dependency is really dog whistle for what happens if US tries to cut off PRC SLOCs in which case it's really a discussion on resource security not autarky. And reality is US is as vulnerable as PRC now - we are in era of advanced rocketry where 150 blown up refineries sets US energy and agriculture into stone age, highly automated ag especially vulnerable. In a peer war where homeland critical infra is being degraded, US can feed population as much as PRC, which is to say not at all. All that shale and blessed farm land means nothing if you can't process what you extract. Blocking shipping is just down the logistics chain than hitting production facilities themselves. The entire fortress america narrative collapsed once US adversaries like PRC gained global strike and now US is vulnerable like everyone else.
I've read that it is estimated that China has the largest recoverable shale gas reserves in the world and some think that its oil shale reserves may exceed those of the US.
So it's not that China hasn't got the natural resources, it's that at the moment it isn't exploiting them as much as the US do.
Interesting. Peter Zeihan says (or said about 2 years ago) that the US is currently the only country with the engineering expertise to exploit shale deposits, so Washington could probably prevent China from exploiting that resource for a decade or 2 if it wanted to (i.e., by making it illegal for petroleum engineers and experts in the US to work in China).
Only friendly neighbours on the same continent, vast swaths of some of the most fertile land in the world, water access to Europe AND Asia, etc.
Regardless of the difference between Chinese and US citizens / culture / government, geography will always remain an advantage