Why would he have not mentioned learning Torah? Certainly the Gra would have. Is it possible that he had noticed that Torah alone does not produce the kind of answers he was looking for?
It seems the Gra and the Rambam both must have seen the same.
The program of the Rambam would be to learn the יד החזקה the Mishne Torah, Physics and Metaphysics. The Gra said that to the degree that one is lacking any knowledge of the seven wisdoms to that degree he will be lacking in knowledge of Torah.
So they are both thinking of a polynomic theory of value. Torah provides an "in" into Numinous value. But they wanted a balance of values.