thinking about ethereum will reach 1000$ in january will be crazy because it is not possible to rise such quick in just a month, and nearly new year already and there is no sign of ethereum rising, it is still around 700$, so i wont think that really can happen.
ETh rose from 28th of May from 159 to 391 on June the 13th. A rise of 232 dollar in just 16 days and it more than doubled.
December 7th 422 to 721 on the 14th an increase of 299 dollar in a week. A week after that it hit 821. So in 14 days it increased 399.
So obvious it is completely possible and very realistic as well.