For whatever reason, I got to thinking about the death of a cool Batman supporting cast member, Sarah Essen, the second wife of Commissioner James Gordon. Introduced in Frank Miller's Batman: Year One, Essen returned to the books during Alan Grant's great Batman run (very clever idea on Grant's part) and ultimately married Gordon. She was then killed by the Joker at the end of No Man's Land. Her death, as you might imagine, was quite traumatic. However, she basically has now been erased from Batman history, in that the last time I recall her even being mentioned was about four years ago. That got me to thinking of another cool Batman supporting cast member who was killed off - Stephanie "Spoiler" Brown. She, too, has basically been erased from Batman history (although Robin occasionally mentions here). This made me come up with what I call "The Erasure Point of Comic Book Grief."
Essentially, the concept is this - there is only a certain amount of grief that a character can suffer before it just overwhelms the entire basis of the character. Therefore, to avoid this, writers will just simply choose to erase the effects of a particular character's death.
To wit, Commissioner Gordon's main point of grief is that the Joker crippled (and perhaps tortured - I do not know what the current stance is on that point) his daughter, Barbara (Batgirl/Oracle) Gordon.
His wife ALSO being murdered by the Joker is just way too much, and as such, it just doesn't get referred to, because doing so would just be overwhelming Gordon with grief.
In the late 80s, after Jason Todd was killed, Batman basically went a bit nuts - that a child in his charge was murdered, it was too much for him to handle. So, later, when a SECOND child in his charge, Stephanie Brown (who was Robin for a short period in time), was murdered, Batman would, theoretically, REALLY lose it, right? You can't go nuts over ONE kid dying, then be okay when a SECOND kid dies, right?
But since no one wants to write a nutso Batman, they just have erased the memory of Stephanie Brown from Batman's history. He just DOESN'T react to her death. No real reason, he just doesn't.
Peter Parker constantly laments the deaths of Uncle Ben and Gwen Stacy, but note that he almost never reflects upon the death of his best friend, Harry Osborn, right? That's because even a character as built upon grief as Peter Parker can't spend THAT much time grieving, so Harry is basically erased from his history.
It really makes you wonder, though, what the point of killing off good characters like Sarah Essen and Stephanie Brown are, if their deaths end up not even really having any effect upon those close to them?