Petahash?
Is this a rhetorical question? If so, basically the home miner will die out due to increasing electrical costs with little to no ROI. Serious mining will definitely move into the datacenter.
2014 will probably be the death of the hobby miner.
Even datacenters will be unprofitable before the end of 2015
No matter how you slice it...difficulty will be forced to level out.
What is price rises? = back in business
It won't matter...you simply won't be able to power the facility.
Before the end of 2015 you will need a heavy industrial service to power a data centre. These types of services are at transmission voltage and are typically reserved for powering entire cities or heavy industrial facilities such as vehicle assembly and production plants.
I havn't run the number but I am guessing there will simply no way on the planet to power a mining facility.
The only way that difficulty can continue to rise is improvements in technology...in other words better than 1W/GHs.