I think the reason why the hashrate is so high up is not the amount of GPUs or ASICs being produced being added to the network but its the old GPUs which were never mining start to mine for the first time.
People either are seeing crazy profits and decide to mine themselves with Nicehash or they see the crazy amounts of money people are selling their GPUs for on Craigslist and eBay so they decide to sell their GPU at a great price and either wait a few months to buy some newer and better GPU or just stop gaming all together. Or game with some old GPU they had laying around. Then that GPU which was never mined before, finally starts mining and adds to the hashrate.
People either are seeing crazy profits and decide to mine themselves with Nicehash or they see the crazy amounts of money people are selling their GPUs for on Craigslist and eBay so they decide to sell their GPU at a great price and either wait a few months to buy some newer and better GPU or just stop gaming all together. Or game with some old GPU they had laying around. Then that GPU which was never mined before, finally starts mining and adds to the hashrate.
There is truth to this. Eth is back to 1720 today. I still think it can top 3k in the next 3-6 months.