My 2 cents: Kurt Cobain was a genius, and like most people of that character,they have a tendency of "falling over the edge".I am also aware that he wasn't ready for the superstar status...it bugged him.He was obviously a sick person, although not by choice.
We can't really sit back and judge others' by what is told in the media.Kurt was obviously a tortured soul,yet brilliant.To the best of my knowledge, very few people set out to become addicts, or alcoholics;or people with psychotic personalities.Their problems are beyond their reasoning.
Only time and luck, and the intervention of others' who've been down that road >may< be able to reach these tortured individuals in a meaningful way.Nobody starts out to become disfunctional,and/or anti-social.
Entertainers have the highest rate of addiction/alcoholism(the same thing,really;just different drug),of all occupations.Fans willingly provide drinks,drugs, and sex to their idols.
People who exibit extreme talent in any form tend to be somewhat unbalanced mentally.I'm thinking of Manic/Depressives,Schizophrenics, etc.These people are driven by a chemical imbalance,and also have a need to "Self medicate".That works for a while, but once addiction sets in,they have at least two problems.Addiction, and Chemical imbalance.
Here are some of the people I am aware of who are or were extremely talented,but also are or were full-blown addicts/alcoholics:Eric Clapton,Keith Richards, Nicola Tesla(inventor of A.C. electricity),Eddie Van Halen,Johnny Winter,John Lennon,Sigmund Freud(grandfather of psychology/psychiatry),Hunter S. Thompson(writer),"Alice Cooper",Pete Townsend,Stevie Ray Vaughn,Jimi Hendrix,Janis Joplin,Jim Morrison,Grace Slick,Sir Winston Churchill,Richard Burton,J.F.K.,Beethoven, Mozart,Elizabeth Taylor, Ozzy Osbourne,Betty Ford,Hugh Grant,John Phillips, MaCkenzie Phillips,Bret Michaels,Robert Downey Jr.,Melanie Griffith,Drew Barrymore,Nikki Sixx,Carl Jung,Charlie Parker,Chris Farley, John Belushi,George Jones,Keith Moon,John 'Bonzo'Bonham,Bon Scott;and Steve Clark....The list will go on forever.