That definitely possible.
BTW I strongly believe that this huge difficulty increase in the last months is due to alt crash.
For quite a while during 2017 ETH was not the best coin to mine, there were plenty of scam coins with much higher profitability.
Right now the market seems to get closer to fair value, so all those dummy projects are slowly going down, making ETH the best coin to mine again.
Basically everyone is mining ETH right now.
Yes but that is due to scams. Scammers at moment are analyzing the market, their plan to scam people was better than they thought it would be, scamcoins like ripple, stellar, cardano, iota and tron made them with a huge balance sheet to account the money they made for. They will have some time off before they start scamming more people out again.
The real reason scammers turned their crypto to usd or other scam currencies is the fact they knew popular coins would tank due to asics. They sold before everybody else and now they are waiting for the bottom and will start the pump scam as soon as the decision is made by the top mafia men.
The rise of the difficult on equihash is also questionable. Asics on eth network means asics on zec network.