Maybe you havent been paying attention, but with Bitcoin the relationship between price and difficulty is strong, this has to do with the investment people make in mining hardware, and the difficulty isnt going anywhere but straight UP in 2014. It may begin to plateau in 2015-2016 as ASICs reach the limits of current manufacturing tech like 20nm and below, gains in efficiency will become increasingly smaller and many small players get squeezed out of the mining game if they havent already.