The question comes down to two considerations, or ways of getting into a new bike.
1. Can I afford to, at this moment, spend 2K on a fat bike?
2. Can I buy a decent fat bike platform for less, and upgrade as finances allow?
If you have disposable income and the entry price is no problem, a bike in the 1.5-2.5K range will always perform better. The frame and component specs are probably at a sweet spot there. However, not everyone has that kind of money to spend all at once and/or you have to consider just how much you will ride a fat bike in comparison to the $ outlay for entry.
Here's a sub $1000 FB that is Al frame, SRAM 1x10, hydro disc and 5" capable. You could buy that, probably ride it for all intended purposes, and upgrade any parts along the way as additional money becomes available. You're in, riding, without breaking the bank.
http://www.bikesdirect.com/products/...-five-inch.htm
Another avenue is buying used. A lot of people get fat bikes as a novelty, ride them a bit, and sell them on. I bought my Spesh Fatboy (new $1700) for $700 gently used. Over time I've upgraded saddle, pedals, dropper post, wider range cassette, rack/cages, frame bag. I have ridden that thing everywhere; trails, snow, sand, bike packing and mtb. Excellent bike for the price.
