1 is that it doesn't take quantity of land but quality of land. Being in the right place has everything to do with it.
Your statistics about the amount of "foreign-owned land" offer no assessment on the
quality of the land they own. And I'm not ready to accept "it's the best land, trust me" as granted.
The second thing is our military is eat up with foreign agents and even "Americans" who hate America so there's always inside help available to them.
If our military is already "eat up" with double agents and traitors, I don't see why
the amount of land owned by the Chinese is even relevant. If they already have
people on the inside, what does it matter how much land they've legally purchased?