... what we get in weaker bones, we get in more refined minds ...
There are a lot of evolutionary trade offs, but weaker bones and refined minds are the two things that do not trade off against each others
A refined mind (for example, such as the one in Homo Sapiens Sapiens) consumes 20% - 25% of the total energy intake of the individual
To obtain a more refined mind one does not need to make one's bone "weaker" --- on the other hand, supercharging the intake process, for example, eating meat instead of digesting straws --- can supply the additional "energy consumption" that a refined mind needs
If there is one trade off for weaker bones is that we humans are becoming better swimmers
As our bones become weaker, our bones become lighter, and lighter folks can float/swim more easily in the water
It is thus no surprise that the vast majority of those who have won Olympic swimming gold medal are mostly from the Caucasoid tribe --- for the Caucasoids have (relatively speaking) the lightest bones among all the humans