Here intelligence means the rational organisation and use of the amount of knowledge and experience of the game of chess. It does not imply that chess players are necessarily more intelligent in spheres apart from chess, although it can help. This and nothing else. Machines cannot think. Observe in how many ways this expression contradicts its own content.
Intelligence is a faculty of the artificer of anything artificial.
The artificer, to possess the required intelligence to create intelligence, would have to be a living entity. A machine is not a living entity. If the artificer had enough intelligence to understand this he would, at the outset, abandon the attempt to create an existential impossibility. The meat heads do not possess such intelligence. This is not because the machines are becoming more clever but because, under the influence of modern philosophy, their builders are becoming more stupid.