With my question above, I was alluding to the fact that a blockchain with higher difficulty is more secure, the lock on the safe is harder to pick.
Understood. This is what we are doing with HyperStake. It has the highest difficulty of any PoS, by order of magnitudes. Some specific code (read
here if interested), just reputable people, good code, good karma, good promotion and no bullshit like "we'll replace BTC". What I mean is: if you have all the population of a country securing the blockchain, you can be pretty sure it will be secure (out of exploit, of course).
You raise interesting points, especially regarding network setup/maintenance costs and the deep pockets of some groups. Although I still think it would be cheaper to hijack SHA256 miners if a big player wanted a POW system (loyalty dissolves quickly behind closed doors) miners will work for peanuts compared to establishing a centralised body. And also a widely spatially distributed network is far superior to attack resilience.
I believe corruption scales worse than a full-fledged on-purpose solution. In other words: hijacking SHA256 is good but there a better solutions, especially if you are thinking long-term.
My prediction is that we will see a fractional reserve system atop POW crypto before fiat. Miners initially sharing the spoils of the debt repayments (and transaction fees).
An
interesting article about fractional reserve in crypto and why it is a dangerous road to take but could be coming.. And
bitcoin.it wiki article on it (did not read, probably interesting, but lazy).
edit:
a truly anonymous blockchain will never be allowed to flourish.
Keyword is
allowed 
If a government were to adopt cryptofiat they would also be establishing a convenient means to leave their fiat for something else.
Cryptofiat Law, January 1, 2017. "The only cryptocurrency that can be bought with euros/dollars is CryptoEuro (EUR)/CryptoDollar (USD). Violators will be prosecuted. Natural persons of age 18 or more will be fined of 1260 $/. Natural persons of less than 18 will have their parents or tutor pay the fine. Officials will be fined 1520 $/ and businesses will be fined 25,200 $/." (pure fiction,
of course)
"A piece of paper is stronger than any technology" - Agent from the DRCI (France counter-espionage agency)
Voilà!