North Korea still relies on the PRC's tolerance and patronage, and the PRC doesn't prefer any outcome that boosts the influence of the US and South Korea. But the PRC's influence and patience with North Korea are limited. Some of the Wikileaks cables indicate China has begun backing away from the regime:
http://www.guardian.co.uk/world/2010/nov/29/wikileaks-cables...
Until recently, China hasn't liked to take a direct approach to many aspects of international affairs. So they influence countries like North Korea, Pakistan, and Iran as tools to achieve their political aims.
They aren't whole-hearted supporters of all aspects of the North Korean regime, frankly, I'd say that they don't really care about what happens in North Korea, as long as they are achieving their foreign policy goals.
A collapsed NK state creates more trouble for China in the form of refugees than a still-functioning one, so we see enough aid for them to keep functioning.
An occasional diplomatic poke in the eye to the US helps China too, but that's a want, not a need. Don't confuse the rhetoric with the reality.
I think they let a US/SK operation clean up while issuing various diplomatic missives decrying the violence, then wrangle a treaty barring major military installations or exercises in northern areas of, and establishing free trade with, the reunified Korea.
China is a very different, and very complicated situation, but they are currently enjoying more political influence than at any time in recent history, and as they are poised to become a dominant world power, North Korea is a liability that they may well decide that they cannot afford.
I would also point out that our respective notions of "live on" must be a bit different; assuming that the data I've read can be trusted, North Korea has almost no paved roads at all [1], which means that the movement of supplies throughout the country is badly hindered. Given the well-known height differences between North Koreans and their South Korean neighbors, the gulags and other oppressions mentioned in this article and others, the threats which North Korea uses to squeeze aid in the form of energy and other supplies from other nations, their nearly complete lack of electrical lighting after dark, and what's known of their trade with China, I find it difficult to see North Korea as being on anything more than the barest of life support from China.
[1]: http://www.tradingeconomics.com/north-korea/roads-paved-perc..., among others.
Hard to tell. On the other hand, their influence over North Korea is an asset they can use in negotiations with other superpowers. Plus, they start to look good in comparison.
China is glad NK exists as a buffer against the US zone of influence (South Korea, Japan, Taiwan), but NK causes China a lot of problems too (eg, there is a crystal-meth problem in the border zones because North Korea produces it as a medicine(!!)[1])
[1] http://www.thedailybeast.com/newsweek/2011/06/19/north-korea...
Both countries invaded Iraq for oil at the command of George Bush II.
Both countries have ~30,000 imperial troops stationed there.
Both countries toe the imperial line on foreign policy.
Why can't Americans see their own Empire? The rest of the world does.
It's my understanding that NK is far from a PRC puppet state, and have a strained relationship, but being that NK depends heavily on China for it's continued existence and security, they do have some sway.
Kim Jong Il has conducted several actions, like the 2006 nuclear test, which has embarrassed and/or annoyed China considerably, underneath the public facade.
Some pertinent links:
http://www.cfr.org/china/china-north-korea-relationship/p110...
http://en.wikipedia.org/wiki/People%27s_Republic_of_China%E2...
