“The introduction of GA glass cockpits has not led to expected safety improvements”; but what was expected.
An associated presentation suggests that the expectation was an overall improvement in safety and not anything specifically. The ‘glass cockpit’ accident rate trends towards IFR flight and with lower experience pilots. Thus the failed expectation may be related to problems with ‘glass’ in providing situation awareness via the displays, or that the pilots lack instrument flying skills either generally, or specifically in glass cockpits.
From a very limited evaluation of a modern ‘wide screen’ GA display, the capability for accurate instrument flight appears less than with a conventional format. Whilst large scale ‘ground’ visualisation provides attitude information it can detract from speed and altitude awareness.
Some displays have been promoted as presenting the big picture instantaneously, but IMHO none are as good as ‘dial’ instruments - ASI, Altimeter, and VSI.
It is the skilled use of these instruments which enable the formulation of the big picture. This is the mental model of the aircraft’s flight path and which is taught and enhanced via an instrument scan.
Many commercial aircraft EFIS suffer similar problems, but the difference in comparison with GA could be greater use of automation, which might alleviate some of the EFIS weaknesses, and higher instrument flying skill levels, although these may suffer derogation with automation use.