IMO, there is now the third group, the laid flat youth who have become parasites living on their parents' retirement incomes. Automation will only make this group larger over time.Completely incomparable.
Actual surveys including some already posted here (I can't find easily on mobile but you probably can easily) show that the most discontent fall into 2 categories:
1. Urban, post 70s/80s who are the "bagholders" of the real estate crisis that bought high and are seeing their imaginary wealth go down.
2. Boomers in rural areas who missed out on the benefits of reform altogether.
Both demographics are now relatively old and have something to lose. Boomers have their pension to lose and the urban middle aged have their remaining property to lose, as well as their lives.
In 1989 the protestors had nothing to lose except their lives but had absolute power to gain if they won.
The problem is that unlike in 1989, mere reform is not enough to solve the problem. The issue is that these people are entitled. They are not satisfied with living in a safe society with good infrastructure. They want a society where they personally benefit from privilege and fuck anyone else who gets in their way. This toxic mindset has already brought down several other countries. A policy change to accommodate them would destroy actual trust in the government by everyone else, as privilege is inherently exclusionary.
Since reform will not work, further repression is the obvious solution. They might not be happy but making them powerless to lash about it would safeguard society as a whole.
They can always self deport elsewhere - without much of their money that will be prevented from leaving with capital controls - if they believe that China is too harsh on them.
This is not a problem unique to China though. Perhaps at some point in the not so far future, the governments will need to collect tax of some sorts on robots for the jobs displaced.