In the near future I see a lot of miners being turned off after the big dump of the halving. We'll climb price based on speculation and then when the magical moment hits we'll see huge sell off.
If the price is below $700 after the having, most high electricity cost miners will shut down their miners.
I don't know about that with the recent S9. Your getting a miner that is 2/3 more efficient (approximately). So at 700 dollars a lot I think could remain with the new gear. Some old gear I do think will come off, but all depends on BTC price after having which is hard to speculate.
Right now with BTC skyrocketing it's hard to say what will be profitable at what electricity rate. But with S9 there will for sure be it.