The problem with Bitcoin is that POW is an unbounded competition of who can provide more computational power, ie. energy, to represent a consensus. Comparing the energy usage to Argentina, Island or any other country is therefore just a snapshot of the issue: Miners are incentivized to either increase the efficiency of mining, or invest more energy -- and because the latter option is easier, we see power usage rising and rising, without it having any influence on the performance or functionality. The only imaginable bound is all the energy that Humans can dispose of, but I think that if that is even being considered, the means have been mistaken for the goals.