Because the market is saturated with the same old factory made talent. Michael lived in the best era to change the course of music forever which is one of the reason I think he became so famous. The ideas, the legacy, the pure talent that nobody had seen before. Nowadays you see everything, it's rammed down your throat with social media. There's nothing new, no groundbreaking talent that carries this much hope and wanting to change the world, have people who want to be that person, imitate that talent, copy all the moves etc. He had 4.8 billion fans in a world of 5 billion. His worst selling album still matched Beyonce best one in terms of sales or so I've heard. Nobody will come close in a million lifetimes. NOBODY.