You're saying that a person who inherits money can't have self-esteem based on what he then goes on to do with it, since he wouldn't have been able to accomplish the same things without it (which I think is arguable, depending on what you mean by accomplishing the same things).
But anyone born in an industrial, Western society is already starting out way ahead and can then go on to accomplish things they otherwise wouldn't have been able to if they were born in Iran, or during the Dark Ages, or whatever.
It makes absolutely no sense to say that one's self-esteem is invalid if they didn't start from an absolute null point. Nobody starts at an absolute null point. So the issue of how much extra one might inherit, as such, is morally irrelevant.
This is just progress.
In the case of the thief, however, it's just parasitism.
AshRyan got a reaction from AlexL in Isn't inheritance theft?