exactly.
I know people hate Marc Andreesen for saying this but the likely scenario in the long run is enormous mining syndicates around the world being regulated in such a way as to PROTECT the Bitcoin network and discourage monopolies.
I don't necessarily see it that way. Most likely there will be both, giant mining farms, as well as smaller enterprises that use local advantages such as cheap energy or technological advantages such as more efficient chip designs.
The great thing about bitcoin is that the blockchain and mining was specifically designed around allowing an anonymous creation of new blocks/coins through PoW.
At least for now it is pretty hard to regulate who can or cannot participate in mining.
[edit] the irony in this is that we might observe something similar to the arms race of the cold war in mining if bitcoin gains wide adoption
Cheap energy and technological advantage are things that can be leverage much more seriously by giant mining farms than smaller enterprises.
One alternative that should be kept in mind is appliance mining where energy consumption/heat from the miners are effectively recycled for other purposes. This could certainly improve and increase decentralization.