I'd like to know what happened that made her decide to scrap this as a single.

It was cancelled like 2 days before the Grammys and she decided to sing AIA at the last minute.
With the Grammys, a video, etc this could have been a bigger hit. It's only problem is that it's not very radio friendly but I still think it could have hit number 1 off the momentum of Hello alone and given a bigger boost to the album.