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.
And what makes most people happy is having a rich personal life, rather than achieving their political goals, I've found.
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.