Part of the problem was that doing the work to apply those insights and doing so in a way that beats trained humans is hard because until recently those models couldn’t handle all the variables and data humans could and so ignored many things that made a difference. Now that more data can be fed into the models they can make the same or better predictions that humans can make and thus stand a chance of outperforming them rather than making “correct” but poorly-informed decisions that, in the real world, would have lost games.
Part of the problem was that doing the work to apply those insights and doing so in a way that beats trained humans is hard because until recently those models couldn’t handle all the variables and data humans could and so ignored many things that made a difference. Now that more data can be fed into the models they can make the same or better predictions that humans can make and thus stand a chance of outperforming them rather than making “correct” but poorly-informed decisions that, in the real world, would have lost games.