@ GroundProx
I can't find a ref to the advanced GPWS that was installed on the jet. Maybe it had the basic "vertical" look and a map and GPS.
Would seem to me that even flying manually and semi-VFR that such a system you referenced would have saved the day.
I can only relate to my own experience in military systems. Our terrain following feature was very helpful in marginal weather, and we had a "cross-scan" mode that showed all terrain above you and also provided vertical steering for the stuff in front. later systems looked "into the turn" for the vertical steering. It made very low-level flying comfortable.
Flying into a vertical cliff without a forward-looking system seems what happened, unless something happened to distract the crew. By the time you get the "pull up" warning it is too late.
This is a very sad incident, and my heart goes out to all the innocent folks. I shall not forgive the crew unless something is revealed that the jet had a problem.