The problem is that you are comparing sales that use a good keyword as the primary word. You are using "Back" as the primary word. Which, while it does roll of the tongue better than "back up" does not directly jump you to that.
You also have to remember that resellers do not pay much for brandables unless it is super premium. This is not. There is a lot more risk in brandables as they have less inherent value. I've seen better brandables go for less than $100 here on Namepros plenty of times.
Sure, you might find a enduser buyer willing to pay 5 figures for it, but I would find that highly unlikely and you might need to wait 10 years for such a buyer. Also, please compare it to domains listed on sites like Brandbucket that end with "ify" but are of a higher quality - they tend to be listed in the low-mid $x,xxx as I stated (I disagree with the $1,000 only and didn't post that).
Hope this helps!