we still need people who are able to pursue specialized goals unencumbered by the overhead of caring for biological progeny. we also need young people who are willing to die for idealistic reasons.

There's only about an infinite amount. I could easily claim that Picasso's main purpose was to create art. That has nothing to do with raising a family. Sure, the bajillions of dollars artists make can feed a family, but they could have opted for other forms of income, raised a family, and not made anything in the art world. How about Tesla? What if my purpose is to demonstrate decentralized fuel production? I don't see anything there directly related to a healthy family. Again, there are nearly infinite examples.