If this proves anything, it is that self-reporting is dangerously misleading and the answers depend very much on who is asking.
BTW, don't forget this
"There is another trait that took me many years to notice, and that is the ability to tolerate ambiguity. Most people want to believe what they learn is the truth: there are a few people who doubt everything. If you believe too much then you are not likely to find the essentially new view that transforms a field, and if you doubt too much you will not be able to do much at all. It is a fine balance between believing what you learn and at the same time doubting things. Great steps forward usually involve a change of viewpoint to outside the standard ones in the field. "
I suspect you are suffering from this. The only place I look for absolute truth is mathematics. When people write, you must pull out and find your own truth. Don't be upset about it if it doesn't fit your thinking. It's entirely possible to disagree with all of it and yet find it incredible useful.
Strictly speaking, these two claims don't contradict each other. Talking to a book writer/researcher in an interview doesn't count as talking privately.
Why? Because you think it's poorly argued or because it challenges the idea that the family is not the ultimate reward?
Nearly everyone he talked to (many Nobel Laureates among them) said their greatest achievement was raising a family or something in personal life.
So I think it's a relevant question if truncated in spirit for brevity.
The reasoning is almost entirely post-hoc. He observes many successful people and their similarities and then claims "I have now told you how to succeed." p(success | trait) != p(trait | success). Hindsight bias is at play.
He makes other weird statements: "you are automatically condemned to waste the rest of your life (see Einstein above)." Mr. Hamming is a difficult guy to please.
Mihaly Csikszentmihalyi studied many successful individuals in a systematic way and acknowledged the inherent problems with this approach. Read his book instead of this: https://www.amazon.com/Creativity-Flow-Psychology-Discovery-...
Finally: "Those who have done really great things generally report, privately, that it is better than wine, the opposite sex, and song put together."
This is strongly contradicted by Mihaly Csikszentmihalyi's evidence. Nearly everyone he talked to (many Nobel Laureates among them) said their greatest achievement was raising a family or something in personal life. I can't claim this generalizes, but I can provide it as a stark counterexample to Hamming's claim.