Yeah selfishness is not a virtue. But I suspect the people who feel guilty for gaining money are afraid of something more inside themselves than anything in society.
Besides being morally wrong, selfishness is stupid. If you don't have customers you don't have any more wealth. Whether you write books or sell candles.
You also have to define selfish. Selfish doesn't mean when you look out that your family or yourself alone have comfort and luxury. It is when you want to tip all the scales so much in your favor that there are clear problems on the lower end. And as that scale gets more one sided, the middle and soon your own neighbors will feel the pinch.
By then they'll probably guillotine you and start over so it works itself out.