That only applies to the third question. Hackers don't care about the miner's incentive, and neither do governments. Besides what we're seeing right now is less companies building mega-mining farms and a more uneven distribution of hashrate.
Nope, wrong again. In reality there are more and more mega-mining farms being built. Just look at the hashing distribution right now and where we were this summer with GHash.
As more of these continue being built the risk continues to be distributed effectively rendering hacking attacks and/or government takeover ineffective.
Is GHash a mining farm or a pool? If it's a pool then your point carries no weight as miners simply pointed their machines to other pools thus decreasing GHash's hashrate. A giant mining pool is not the same as a giant mining farm.
Ghash is a pool but I'm sure they have their own farms as well.
Anyway, this irrelevant to the situation and I find it a bit strange for you to point this out since it effectively defeats your point as well.
If Ghash is not a concern for you then we can safely say no private, unique entity's mining farm as even approached the necessary 51% hash rate. Considering more mining farms are being set up by other individuals we can safely say the danger of mining centralization is decreasing every day