There is a different break-even point for each miner, that will become more and more apparent with decreasing bounty and diversity of technologies (FPGA, GPU, ASIC, CPU botnet) deployed. Most miner will soon be out of business. Mining will centralize to those able to keep up with innovation and investment required, those few commanding the majority hashing power will soon build an Olygopoly
http://en.wikipedia.org/wiki/Oligopoly and ensure transactions deemed too cheap will not be included to the blocks they create and have therefore marginal chance of being included by the few challenger outside the ologopoly.
The oligopoly will manage transaction costs high enough for their profit but low enough not to provide sufficient incentive for real innovation compared to their technology.
Think of OPEC oil price management vs. green energy.
This is a fallacy simply because every miner's circumstances and operating conditions are different. Some places will have cheap power, but expensive hardware, others will mine for a few quick bucks, while others are trying to make solid profits. ALL however realise that any monopoly on transaction processing means they lose, BIG time. No miners will seek a monopoly since to do so will endanger the value of the very coins they are collecting. Cheap or near zero fee transactions will be added for many years to come, and frankly if the fees are too cheap or non-existent on a transaction then the person making the transactions needs to suck it up and pony up the dough for what the majority of miners consider a reasonable fee. Fees in transactions don't in any way mean the blocks get solved faster so your assumption that an oligopoly based on the majority of miners only processing transactions with fees included is completely wrong.
Competition in mining is definitely going to get fiercer as new technologies come on board but everyone is in the same boat, just because one group is surging ahead with a faster, cheaper solution doesn't mean everyone else is standing still, nor does it mean new techs have that much of an edge. GPU mining is cheap and losses are hedged because their equipment can be sold on, it's a low risk and flexible investment, FPGAs or AISCs, very specialised, high cost to implement, long lead times, cheap operating costs. Each has their advantages and disadvantages.