Great analysis! My wife and I went through this when our kids were born. Genetic diseases were the deal breaker for us. Basically, if you need stem cells, it's unlikely that you want your own cells that likely caused the problem to begin with. Also, the chance that one's cord blood is useful to another family member isn't very likely so that option is out as well. It really remains to be seen if private banking of any bio material will be useful when compared to public banks. In the absence of a major and specific scientific breakthrough, there is just no compelling reason for private banking.
In the end we donated their cord blood and, if needed, we'll use the cord blood bank like everybody else.
Only through hard work and perseverance can one truly suffer.