Board Thread:General Discussion/@comment-35233810-20180418165518/@comment-1429792-20180419105338

I think an important credential to become a captain is that you are dead, residing in Soul Society and have actually joined the Gotei 13, none of which Ichigo has fulfilled. If he ever becomes a captain, it will be after his physical body has died at some ripe old age, assuming he retains his full powers when he is sent to Soul Society.