It seems odd that so few understand the dynamics of exponential growth on even a basic level.

The difficulty level cannot continue to double every few months forever. You can start with the laws of thermodynamics, and realize that in just a 5 more years of doubling it would utilize the entire energy output of the sun for hashing with even quantum computing. It had to stop increasing at that rate, and it did.

Additionally, from a commercial standpoint, many endeavors were built with a specific BTC/$ value. If you built out a large mining operation based upon $500/btc you are bleeding and will probably shut down in the near future. However, if you bought a miner for your home and are running it, you are dancing in the street. You can watch the $/btc rate jump from $100 to $1000 and back to $100 and afford to keep hashing. You can hold pretty much forever, unlike an ongoing major mining concern. And when the difficulty steadfastly refuses to increase, the life of your gear just got extended, and so does your ROI.

My crystal ball predicts a movement towards decentralization of mining. Larger mines find it difficult of survive large $/btc swings for extended periods.

PS: Try running a mining calculator on some current devices where the difficulty increases around 2% per cycle and see what happens. It's raining ROI like never before for devices you can have delivered in a few days on the secondary market. Expect prices on second-hand devices to go through the ceiling shortly. Even at current prices, a 1Th machine with 1KW usage will make around $85/month after electricity costs. Projections at 2% per cycle says 100% ROI in 3 months, and profits continue well into 2016.