If the DAO hacker declare that he will not dump his coins, the price of ETC will rise a lot. And he will have enough to support the development.
The DAO hacker does not necessary like the Ethereum or the ETC. He is in for the money. So the price of ETC might crash to zero.
That could be true. We should not pin our hope of the success on the actions of the a single hacker who might not care about other people.