I kind of noticed this also, although I don't usually get as many good ones out of ANC.

I was thinking it had to do mostly with the holidays.

In the past, I have seen times where they only had these "useless" fares that make you take a day off work or travel only on Saturday. Then, they suddenly have some good ones again.

So, maybe it's just a holiday/end of year thing or maybe it's not. I usually just cross my fingers and wait for something better!