Great post.
I agree with you on this quote:

For ETC, Code is Law. The immutability of Ethereum Classic's blockchain will be its defining pillar.

I also believe that is why ETC will stay and not disappear. It's a major asset for the definition and application of future smart contracts.

And the best proof we have is that it already re-spawned once from ETC.

But this does not mean that ETH will die. Imho, ETH has more professional applications and will moon as well when companies and businesses will start to implement blockchain based services. ETH showed that attacks could be "cancelled" (bad word... I know) and proved the resistance of the system. It's definitely a plus for a mass-adoption.

The ETC/ETH split is a good thing in the end: These 2 currencies will both remain and have different roles based on their characteristics (immutability vs. resistance to attacks).