51% attacks normally require 51% stake. It's true that large stakeholders will occasionally have several winning block scores in a row, which lets them create a viable short fork, but it's not really a problem. Short forks just mean that users need to wait for several blocks if they want a high degree of certainty that a transaction is final.

51% attacks could also be more feasible if an attacker can manipulate entropy, but the usual safeguard is to derive entropy from verifier addresses, as NXT does, so that manipulating entropy will cost a verifier their block reward. Then require verifiers to have a certain minimum account age, high enough that grinding attacks become infeasible.

Certainly more complex, but with the right design PoS works fine while saving electricity, and the cost savings are passed on to all stakeholders.

The majority of the supply was produced rather trivially for a measurably inexpensive amount of captial cost to mint it prior to 2015.

One could surmise the reason crypto isn't banned yet is because nation states have the resources to mine majority stake easily due to the majority supply being created in a short time frame.

I'm not saying it's unrealistic, just that it would be more expensive today than what the article says.

[1] https://blockchain.info/charts/hash-rate?timespan=2years

A case study in censorship though the pools has proven this:

https://steemit.com/ethereum/@dhumphrey/f2pool-manipulates-u...

Unless a coordinated majority is censoring your transactions, you can't really be censored, your transactions will just be slightly delayed sometimes. Which is normally very harmless.

The only problem here was a poorly run ICO, where prices were dependent on the order of transactions. That wouldn't be the case with e.g. a reverse Dutch auction similar to the process for Treasury bills.

Assuming you are correct, here's something you dint consider - most of the PoS coins need a starting point - mainly the genesis block. These coins are acquired through ICO mechanism. Example NEO. While the current price is 122 USD @ 8 billion in marketcap. But, it started at 0.3 USD and raised USD 28 million. So, China need not buy now 4 billion of coins now, it could have spent 15-20 million to acquire more than 50% of the staking coins.