One can imagine a scenario, where decompression did not occur, but comms and nav became permanently disabled and command authority in cockpit by design or circumstance was left to the autopilot. Then manual authority in the cockpit was eventually regained so there was manual input or control when it touched down/crashed in the sea.
In such a scenario, a very, very, very slim chance of the latter phase of the flight ending well enough that there are survivors currently languishing on escape slides that are not fitted with even an off the shelf $200 EPIRB.