Two of the casualties were tossed from a pontoon at the Thunder River Rapids ride and two others were caught inside.
Enthusiastic Leisure said decommissioning the ride was "the main conscious and fitting game-plan".
Dreamworld, on Queensland's Gold Coast, has been shut since the catastrophe on 25 October.
The firm says it won't revive until a free security survey has been finished.
Kate Goodchild, 32, passed on close by sibling Luke Dorsett, 35, his accomplice, Roozbeh Araghi, 38, and Cindy Low, 42.
Dreamworld: Who were the casualties?
Kin and couple among amusement stop dead