Yes, posthumous fame is a necessary component of celebrity culture, because it is common to idolize someone after death. It makes sense that if a person is idolized after they are famous, that will be even more so after they die. We want to idolize them, and they can no longer do anything wrong.
Posthumous fame is a necessary component of celebrity culture. This is because of the fact that as with all cultures, celebrity culture requires the voices of the past to truly be a culture that is enriched. We must look at the past people in our culture to make it a truly full culture.
I think sometimes it takes a person death in order to see how special they were. We like to take advantage of the fact that we have so long to live,but in reality life is short, its sad. This shows when we lose people, they are gone,but not forgotten, Tupac is this way.
It's not "necessary" because it simply happens as part of human nature. If you're famous, your accomplishments don't change once you die. You are still the hit singer with a string of R&B hits. People don't just up and say "Well, she overdosed in a hotel bathtub, let's forget everything she did."