I hear what you’re saying, I just bought a fatbike myself. I was thinking about going the bikes direct route, it does seem like you get a great component list for the price. My only issue with that was I couldn’t test drive it first, even though they do have returns you would be responsible for shipping and possibly an extra fee because it’s a heavier fatbike. I ended up getting a good deal on a used bike on Craigslist. I hear what you’re saying as far as bikes being too expensive, but I think in the end it’s the price that people are willing to pay. Also I think fat bikes are more expensive than typical hardtails because the wheel sets are harder to manufacture and contain more materials. Also if you plan on taking your fatbike for long-distance bickpacking trips and through the snow do you really want to get something cheap?
The first mountain bike I bought was an entry level bike, I rode it so much that almost everything on it failed and had to be replaced with better components. In the end I could have gotten much better bike for the same price if I would have just bought that in the first place.
You can find good deals on Craigslist or eBay but you have to be patient…..