our society of consumption makes it very easy to feel entitled--whether people demand particular works from a creator for free, or think an indie game should never cost above ten dollars, or use whatever justification under the sun to insist that an artist's commission prices should be cheaper...
artists will, generally, charge what they personally feel is fair, or at least what they think they can get away with. in a kinder world, nobody would be forced to tie a monetary value to self-expression. art is highly personal. self-worth and self-judgment often become tangled up in it, particularly when money gets involved. people work at different speeds, at different levels of experience and confidence. all the client sees is the art, and the price tag. they don't see any of the internal context leading up to any of it.
our society also encourages us to punch down, to blame each other for systemic issues. newer artists are especially prone to "underpricing," since they lack confidence and experience. it's also more difficult for them to attract an audience. i don't see any reason to shame them over it. it's none of my business.
i try not to begrudge anyone for charging more or less than what i, an uninvolved bystander, feel i would personally pay. if i am commissioning someone and i feel they are not charging enough, i tip them appropriately, within my means.
this has better results than arbitrarily guilt tripping a stranger over a topic as volatile as pricing, in my experience.