[variaga]

For security, the cost of the hashing needs to be greater than the value of being able to subvert the bitcoin network with 51% attacks.

If the cost of the hashing power is less than the value, then the incentive is to just buy the hashing power and do the 51% attacks.

So to the extent that bitcoin has any value at all, it's going to either burn an amount of electricity greater than the value of a network compromise, or it's not going to be secure.