Steggall didn’t win Warringah. Abbott lost Warringah. Steggall picked up the seat by default.
Abbott single handedly trashed a blue ribbon Liberal seat so badly that lifelong wealthy Liberal party members and voters actually participated in GetUp rallies in Warringah.
The result - Abbott consigned to the rubbish bin of political history. A destructive era brought to an abrupt end, and Morrison gifted clear air to progress centre right policies. The definitive win-win outcome.