Although this is true on average, if you accept his account of his lifetime effort, it's not clearly true in his case, nor, if he views himself as modeling desirable behavior, what he's calling for.

(Also, among other problems with what you said, not having children until there is a "civilization worth living in" will guarantee a complete disaster of a civilization, with no way to make it worth living in. That's not the actual state of affairs--people are having children anyway--but it's a silly argument. There is a related argument which has some merit, but you didn't make that one, you made this one.)