The picture cost $14, it has grossed $22.5 and is not weakening. It is a success - commercially and critically. I'm not happy about it, but people want to see it. Kevin Costner's last western, the excellent "Open Range," grossed somewhere north of $50 million...
Unfortunately for your supposition, Carnage, the movie may have cost $14 million to make, but you have to add in associated costs such as advertising and distribution before you can conclude that a $22 million gross means the movie made a profit.
14 to make, 22 gross, plus marketing.. its basically slightly over break even right now I would bet... and it won't likely do much more.
The simple truth is, there is only so much a movie like this is going to do, period.
I applaud their marketing style of this movie, very slowly expand, continuing to use the controversy to get folks to watch it that otherwise would have ignored it just because of the hype had it been released nationwide at once... but this is not a new tack, in fact its a tried and true one for a film they know has limited appeal.