The purpose of patents, is incentive companies to share their secrets.
For example, Coca-Cola never patended their formula. So you might think: I can copy it and sell my own right? Well, yes, legally yes, if you ever found their formula, somehow. They been successful for more than a hundred years now in hiding that formula.
Thing is, software patents allowed people to actually patent ideas, concepts, stuff that is obvious and don't need sharing, for example: "ghost racer" is a patented concept, for a while any game that wanted to display to the player his past run by showing a slightly different copy of himself so he can compare, had to pay patent royalty. But the concept is obvious, it is simple, it is there, nobody used a ludicrous amount of money and time to invent it.
This is different than the patent for Michael Jackson dance moves that requires specialized devices, he patented physical objects that required time and money to make, they had a non-trivial purpose on his dance and he had to work to create them to make his dance moves possible. And now that he is gone, the awesome stage tricks he invented can keep existing, because he wrote detailed patents explaining how to repeat his feats.