Does anyone else think that this might call into question the whole concept of the CDA?
It would depend exactly what point the critical failure occurred. Let's say it was some minutes before the point at which it became evident to the crew, with the aircraft descending to establish on the ILS and with the engines at idle.
The engines did not respond when power was applied, either by autothrust or manually. Had they responded already when the gear was selected down and landing flap lowered? We do not know yet. Let's suppose they hadn't for whatever reason - it was gusty day. If the failure was already present it could be masked at this stage.
Let us now insert a level segment in the descent at either 2500ft or 3000ft. The aircraft requires power but does not respond at this point. There is possibly earlier recognition of a serious problem and the action open to the crew is to delay lowering the gear and the flap which could result in the aircraft safely reaching the tarmac even if it touches down tail first.
Any 777 drivers care to comment? Would the 777 make a runway from 3000ft/10 miles, on the GS with power at idle?