depends on whether on a per capita basis, they are net producers or net consumers

Tongsan is in that place because they are producing "too much"

Whereas in, say, pre-Black Death Europe, they had a problem with producing too little
Oh yes

Famously, the Nazi Germans went to war over such pretexts
The State also incurs significant costs

It's like a company - do you think it's feasible to hire hundreds of thousands of graduates, in the hopes you can find and groom the next Bill Gates amongst them?

Even if you fire 99.999% of them after one month, you will probably be bankrupt just from the onboarding process

Same principle

Your defence would be much more believable if China wasn't busy annexing Lebensraum in the SCS