Parts of the Chinese nation are too busy being vastly wealthier than their parents. China has a decent-sized first and comparatively large second world economy embedded in the world's largest third-world economy.
This is true, but the third world economy is not the one that tends to revolt. Tiananmen was driven by students. And that demographic has been effectively pacified by the fantastic urban growth China has experienced over the last two decades.
Putting aside the reasons the third-world economy doesn't revolt or isn't seen actively revolting (being too busy trying to survive, having to deal with local officials and police that are part of the Confucian machinery, not having any significant outbound information channels in their geographic area, etc), the demographic of "student" is a constantly shifting one, and one that has been blocked from learning anything about Tienanmen for a quarter of a century. It is hard to form concepts about something that has been so effectively and actively suppressed, right to the level of the Great Firewall.
By contrast, we can still talk about the various Occupy movements (some of which continue to smolder in various corners of urban centers), just most people don't really care that much, the street theater got stale; that sort of effect is real, and could conceivably contribute to a nonchalant attitude in China towards Tienanmen today, but we won't know, because the Party has decided that everyone must not care by keeping anyone from trying to learn about it.
