Good point. You might let it sit if the Chinese (or others) are dumping steel on the North American markets (or effectively doing so via currency manipulation/devaluation) and it is otherwise not profitable. Perhaps you let it idle in hopes of busting Union demands (as their workers tire of being un/under employed), until the union/business climate becomes more friendly (i.e. North American Union rights/erode and it thus becomes easier to reach profit margins ) . Or perhaps you buy it and let it idle to prevent your competitors from having it , thereby protecting your existing market share... It will sit , until the cumulative lost opportunity cost begins to outweigh the CAPEX of re-starting production , and OPEX costs are sufficiently reduced (due a deflationary environment or constellation of other factors) .

Cheers,

Luker