I think he killed himself. The timing says it all. He dies just when he hired (or bought or whatever) a nice, big, lonely villa in whatever city there was, and suddenly just drops dead. I think that he took one too many pills on purpose. But he was already dead inside. The real MJ that everyone loved and adored has been gone for years.
But why would people follow him to death? Were they hoping to meet him in heaven? Would they enjoy a nice cup of tea accompanied by lovely ladies giving them blowjobs (and possibly a little child for MJ if the allegations were true, which I don't believe)? MJ wouldn't want to bring company to heaven, he just wanted to, or did accidentally, die. He isn't the reason to live. He isn't the source of the Lifestream (FFVII reference). Think this way, if you like his music, you can't listen to it when you're dead. You never met Jackson in real life, you didn't kill yourself then (or maybe you did meet him).