Because the music is legend, and with the way he so insulated himself within his eccentricities which existed on such a lavish, megalomaniacal level, he seemed like could never die, that he was a super-human fixture in the American landscape that would always be there.
I didn't listen to music when I was younger, but when I was a preschooler, I knew who he was, and I somehow already knew he was a preternaturally cool artist and was already a fan quite possibly without ever having heard any of his singles. In fact, I don't remember a time ever where I didn't know who Michael Jackson was. He was always there.
In 1993, he became a toxic figure in a general cultural sense because of the charges of molestation, which hastened his artistic irrelevance, particularly in my mind. Since I considered myself to be on the generational cusp of his appeal, I thought his legacy was permanently finished... I was astonished that not only did he retain credibility and idol-worship among actual performers, those performers were all younger than me. If he could be called a pedophile and hold onto his fans, if in fact he could make new fans, he could always be there.
He was always there. Now he's not.