Man, I understand your point. For real.
But the 51% attack I cannot say it’s impossible, but very close to it.
You cannot attack the chain by just conquering the mining power. This is something very basic on how btc works.
But you know, anyway..
And it's not too far fetched that china might control a big mining pool if BTC would take off.
And yes decentralization doesn't just fix the issue of regimes like china.
It is more controllable than you would like to make it out.
Especially with the great firewall.