Even if we are to believe North Korea makes its own choices, surely it must still follow that if China puts a slow but continuously growing food/energy/cash squeeze on North Korea, that will get them almost anything.

I believe North Korea's dependence on China is a well known fact and the more important aspect. If I posit that influence is much larger than widely accepted, that's actually not important. What is easily provable is whether this 'explosive situation' will fizzle or not - time will tell.

Edit: wording