Amelio and Hancock had only been in their positions at Apple since 1996, both joining from National Semiconductor. However, they were unable to turn Apple around quickly enough to satisfy Cupertino’s board of directors.
Well, that is satisfy the board after Jobs had done his behind the scenes lobbying against Amelio earlier. He would only have been able to come back because Amelio had brought in Hancock to review the sad state of progress on a new OS, and Apple decided to pick up NeXT.