SS,
There's a grain of truth in your understanding of the CFIT incident. The 'whole truth' (a difficult animal to find I'll admit) as related by BA contacts is:
1. The aircraft did not fly into the ground but was well on the way to doing so. No GPWS available at that time and when introduced was immediately referred to as the Game Park Warning System
2. It was a BOAC flight and they did not use the monitored approach SOP. The Mon App was a BEA SOP and became standard in the newly formed BA.
Although I'm not convinced that use of the monitored approach would reduce the incidence of CFIT incidents I feel that it is a useful final approach tool, particularly during a manual approach to low MDA or when flying a coupled approach to low DA.