Why Project Habakkuk made less sense as the war changed

Did Project Habakkuk make sense when proposed but not by the time it was canceled?

Yes; escort carriers replaced its intended role, and the steel shortage that favored pykrete became less decisive.

The original proposal answered a real problem: Allied aircraft needed coverage over the mid-Atlantic, while steel and conventional carrier construction were constrained. As escort carriers appeared in quantity, many smaller mobile decks could provide that coverage without the risks of one immense experimental hull. The industrial argument for pykrete also weakened as wartime production changed. Habakkuk therefore illustrates a concept that could be rational when proposed yet obsolete before completion.