And one of biggest thing that prove i'm right is.. Days gone and Dead Space. Both made by big companies who cares mostly about money not art etc. yet decided to implement it while it's pretty strange in Dead space 1 because.... mining ships with babies?
I can't judge the companies of DG and DS, but both surely have creative people in it who work differently than the money-grabbing managers and the managers know quite well they can't succeed without the creative people and a game-done-by-numbers. It isn't that simple.
Secondly, at least dead space looks like it was intended as horror for the 18-and-up crowd with no compromises. Once you go that way then a few taboo breaks won't cost you many customers and instead increase word-of-mouth and get you new customers. Case in point this quote from wikipedia: "Initially, Dead Space Community Manager Andrew Green stated that Germany, China and Japan banned the game. However, it was confirmed that this was a marketing ploy and that Dead Space was not banned in any country". Oh look, they tried to milk the market niche they were targeting to the fullest

Now, what did it get them? Remember, as a few commenters here said, it is a niche. Quote Wikipedia: "The game, along with Mirror's Edge, was considered a commercial disappointment following its extensive marketing. ... In February 2009, Electronic Arts CFO Eric Brown confirmed that all versions of Dead Space had sold one million copies worldwide.". Okay, so extensive marketing and as we know fabulous reviews across the board and the game sold a measly million copies after 1.5 years! Maybe in this case, without the kid-horror, it would have been even less. But that doesn't mean other games not strictly targeting the extreme horror fringe would experience the same.