it looks to me that mining would be best described as being in a Pure Strategy Nash Equilibrium - cypherdoc
Highlights are mine:

"A pure strategy Nash equilibrium is a profile of strategies such that each player’s (miner's) strategy is a best response ((results in the highest available payoff (block reward)) against the equilibrium strategies of the other players (miners).

A pure strategy Nash equilibrium only requires that the action taken by each agent (miner) be best against the actual equilibrium actions taken by the other players (miners), and not necessarily against all possible actions of the other players (miners). In other words, it's expected for some miners to be malicious.

A Nash equilibrium has the nice property that it is stable: if each player expects 'a' to be the profile of actions played, then no player (miner) has any incentive to change his or her action (no incentive to start cheating). In other words, no player (miner) regrets having played the action that he or she played in a Nash equilibrium."

http://papers.ssrn.com/sol3/papers.cfm?abstract_id=1968579