Doesn't matter what the J/GH is if you can never recover the capital cost of miners even with free electricity, which is where bitcoin mining stands right now.
You couldnt be more wrong. Here is a chart for you:

It shows the network speed where miners would break even after 2 years using the listed assumed variables. Even in the current climate and with current efficiency, we are no were near where (industrial) mining would not be profitable. And the effect of power efficiency is quite dramatic if you consider reasonable electricity cost price ranges (~0.06 / KWh)