My reason for believing China will have to open up sooner than its leadership thinks has to do with its basic challenge: It has to get rich before it gets old.
That is, since China's population is aging, China must get rich in order to take care of them. And since China can't get rich without liberalizing, China's absolute rulers will give up enough power to keep economic growth going.
Why is that the choice? Why can't China get rich enough withoug liberalizing?
More basically, why would China's rulers give up power in order to raise living standards to keep old people in the countryside in comfortable retirement?
If China's rulers value maintaining their position, power, and privileges, why wouldn't the rulers pursue as much growth as they can without liberalizing? And then use brute force to keep down anyone unhappy with that?
You know, the way they've been acting the last thirty years, or so?
UPDATE: So does a letter signed by a bunch of retired communists urging freedom of speech mean that change is coming to China?
Is there a revolt of the Twittering class in China?
I don't know. If the guys still in power and hungry to keep power don't agree with freedom of speech, as long as the guys with guns and tanks obey the rulers, a letter won't mean much beyond a much reduced pension for those letter signers.
As for the Twitter revolution, don't get your hopes up. Action must follow 140-character posts. When you Twitter a king, kill him. Or you'll be the dead one.