@cryptostoday - back in 2009 they were mining with nothing more than our CPU's, then they started mining with graphics cards. Eventually they went to ASICS due to competition to try to get more block rewards. Right now most of the mining happens in China due to the cheap electricity. ASIC mining became necessary to keep up with large centralized electricity companies dumping their excess power in China. At the same time the difficulty had to be increased to ensure no cheating was happening on the network.

Mining pools can be formed to try to compete with the large miners and distribute part of the reward to all participants. Right now ASICS are necessary if you're doing this on your own because the power users will very quickly snatch up the block rewards before you even get past the first series of hashes in SHA256.

The central banks have next to no possibility of ever taking over bitcoin. They can try to fork away without consensus, but the consensus rules punish severely in terms of cost. Who do you think is going to join FedCoin? I most certainly won't. The reality is that central banks will not be able to fork bitcoin away and create their own rules that make it like national fiat. If they do, the SOV (store of value) will be destroyed and the currency will be worthless.