It is completely understandable a project of this nature would require galaxy brains (w/ very lucrative alternatives) and the capacity to burn billions prior to seeing any meaningful returns.
One could easily argue that pursuing a non-profit approach was ultimately ineffective, and that open-sourcing the project would make a for-profit model unfeasible.
However, Sam is choosing to be closed lipped about it, having only made vague references to the potential risks of open-sourcing the project several years ago.