You are getting it wrong OP. Michael Jackson didn't die poor despite the debt that he is owing. Michael Jackson has a multi million dollar estate which he built and up till date, that property is still generating massive income which his three kids are getting their own share from that investment based on the percentage given to them. Michael Jackson asset that he left enough to take of his children and their children children.
True. Michael Jackson didn't die in poverty. He was the King of Pop at the time, and he did leave behind a significant amount of assets. There are rumors that he was in debt when he died, but that doesn't mean he didn't have any assets. In fact, I suspect, as you said, his assets could support his children and grandchildren, especially since royalties are still being paid to this day.
However, behind all this, we can learn an important lesson from the case mentioned by the OP above. Indeed, no one knows how long they will live, or under what circumstances they will die. Therefore, anyone who feels they will not live long should manage their finances and actions as best as possible. A healthy lifestyle is also paramount, as is the case with drugs. Many cases involving famous artists often involve drugs, which is the main problem that led to their poverty. Therefore, stay away from drugs.