When you consider the progress China has made over the last 50 years from the perspective of a typical Chinese citizen, you can see why they make that bargain.
So success would be far from guaranteed.
If I'd be Chinese I'd probably do the same trade they did.
After prosperity, keeping the lid on as hard as it is now is much, much harder. And if changes don't come easily and naturally, I guess you can emigrate.
There would now be political rallies, protests, different factions of people wanting different things, etc.
That distracts from economic progress.
It's fairly clear to me that in many cases freedom of speech and similar rights leads to less stability and less economic growth.
(I'm specifically noting those two because their deaths were epochal events in the modern political history of both countries.)
The OP said they don't talk about it. Doesn't mean they don't care about it much. It is simply they don't have any means, tools or action they could do to change it.
This isn't true at all. China is one of the only places in the developed world where the populace legitimately could topple the government, simply by sheer mass.
Why do you think the party works so diligently to quell dissent and organization while going to extreme lengths to prop up the economy? It would be nearly impossible to hold on to power if the people turned, but nobody is interested in that while they (or their children) can live in a nice apartment and take a holiday in Europe once in a while.
I'm just trying to understand this attitude towards acceptance of losing privacy...
Or is just given up after years of losing to their government?