I expect the "reward halving" to have a significant, negative impact on large mining operations. Another way to phrase this is "income halving" (in terms of bitcoins). Virtually everything that goes into a mining operation is priced in fiat (USD for me). That means electricity, hardware, staff salaries, cooling and so forth. Unless bitcoin doubles in value, a large operation will likely lose half it's "income", and have zero reduction in it's cost of operation. Show that to any large industrial operation (e.g. auto manufacturer), and they will all say it's time to do something drastic (e.g. close plants, lay off folks, etc).

I don't see how a large bitcoin mining operation can avoid this, unless they start to "wind down" in some way prior to "reward halving".