Publishers, like all private businesses, have always been concerned about profitability  But, while it used to be at least possible to get a book published that was unlikely to be popular, and hence unlikely to be a moneymaker, profitability is now the sole criterion
Thus, no matter how much literary merit a book possesses, it will not be published in today' s market if it looks like it will not be popular
It is harder to get a book published today than it once was.