It can't go to 0. Never. 3k seems to be the absolute bottom to me, and we won't reach it.
Here is a chart that you can use that will help.
I have updated it with Bitmains latest offering of the Antminer S9.
https://docs.google.com/spreadsheets/d/11QS1BBV11KNGTF8N_-fdfmjTZ3WzPQFbLfVrl5n6R8s/edit?usp=sharing
Between 2k and 4k to create 1BTC? There is a short window of oportunity to make such things as network difficulty depending on how much hardware does make its way onto it. The network difficulty rises you may never make 1BTC from the hardware.
At this price it may be way more profitable to simply purchase BTC.
Here is an example from the above linked document.
^ UPDATE: Now with two difficulty dates. Presently set at 5% and 1% on the 6th month.
It seems that the network difficulty will be dropping. Perhaps due to BCH taking a little of the mining hardware out of the picture or older hardware being taken offline to to operating costs.