Very good question and the answer depends on someone's personal view of the world and reality.

Here is my interpretation.
I think that we live in a society that pretends to look after the individual but in fact that is just an illusion. Intelligence works better in this scenario most of the time. Let us just assume that society does look after the individual , which is great as we are protected from bad people who could hurt us because they are stronger. Then what happens if you are in a car crash and you are just too weak too get your family out of a burning car, or a tree falls on you when you are walking your dog? Yes information will aid you in this situation but ultimately strength would prevail.

Now let us assume that society fails and collapses.' When the lights go out' Brute strength would clearly be an asset as you could defend yourself and the weak would look to you for protection. This is fine until you run out of a sustainable food source or you get ill from one of a thousand things that would be trying to kill you, from disease to wild animals.

Therefore the logical answer is to be the best you can be physically and mentally, but we generally do not do this. We do not 'need' to so our brains do not see it as priority. I am guilty of this , I like to learn so I do, I want to workout but it is hard so I do less than I should. I still do both but there is always room for improvement and getting the balance is a tricky one.

So in my mind it basically should be a 50/50 split and that way you are covered for all eventualities. The next question I ask myself is what is the best type of mental learning to pursue and what is the best kind of physical training. Philosophy ain't going to put food on the table and massive muscles may not help you in a physical confrontation .

The quote from Socrates sums it up for me. He was one of the greatest thinkers.

Total rant from me but this fired me up. Thanks