Hard to say. I'm watching the historical graphs.

If you graph 10 day average daily fiat rewards (block + uncle + gas x $price in fiat) versus change in daily hash rate versus 10-day average, historically, the only time hash-rate declines is when rewards are less than $100 per GH per day.

That's $36.5 per MH per year.

We're right now at about $15 per GH per day ($5.48 /MH/year), which is the lowest that rewards have ever been, excluding ETH's first few hopeful months, in which they were $0. There are big dropouts at $40 per GH and $80 per GH, which appear to indicate generations of hardware. Also, in the past month, although we have seen a precipitous drop to $20 GH $rewards/hashpower, we have seen both growth and decline, with a total decline in the range of about 10 GH/day. 10GH is more than the entire hashrate of all ETH in January 2017, to put things in perspective. But it's less than 4% of total.

An increase from one day to the next means that mining is profitable for some miners at the $20/GH/day zone, and they added hardware to the network. That's a pretty efficient rig if it's going to be profitable at less than $7.50/MH/year. Probably safe to assume this represents ASIC or generator-attached commercial rigs coming online.

While people have mined at a loss and then hung on, it's only the hobby miners that do this. We're at 270 GH/s. What fraction of that do you think comes from hobby miners?

If commercial interests believe that ETH will go up, they are better off spending their capital to buy ETH (for more ETH/$) than mining ETH at a loss.