All three were geniuses who died prematurely, but I think their stories are fundamentally different. Robin Williams strikes me as a man who fought bravely against his personal demons virtually all of his life until they finally overwhelmed him; comedian or car salesman, his fate ultimately would have been the same. Michael Jackson was doomed by issues in his upbringing and his inability to deal with the pressures of fame; his life was in a downward spiral years before he died, and the outcome seemed inevitable even at the time. Prince, on the other hand, was living the way he wanted to, and there was nothing inevitable about his demise; he just made a stupid, fatal mistake with his pain medication. There is nothing more to it than that.
The Robin Williams suicide affected me the most, because it is so easy for me to see him as an essentially noble character in a tragedy. The death of Prince is a loss to all of us, because there is no telling what music the world will never hear as a result. With Michael, the story of his life from roughly the middle of the 1980’s was just kind of sickening.
That’s my opinion. I could be wrong. If you disagree, don’t hesitate to say so.