An interesting read by @Fundamentals on the mining industry.
At the end of the day, a large amount people engage in mining simply because it's ungovernable and they want to stick it to the man. Few people are in it for the profit. That's irrational from a capital markets perspective.
Proofs are ungovernable and so is being irrational, and this is really the only way I can explain those who choose to dedicate resources to bitcoin mining.
It was also discussed on his podcast Rock Paper Bitcoin here: