I don't think the hashrate will explode so much. I suppose the machines which are now being sold are already mining for Bitmain ... and will be mining until October. Units will just change their location. Bitmain guys are not stupid.
This is the same thing that is in my mine, i posted basically the same theory on a local FB cryptominers page in my country. I received an epic amount of bashing and got kicked out from that group.
