but if an aircraft has EFIS airspeed displayed with low speed awareness symbology overlaid, then this is a 'display' of AoA. Also it is referenced to action values, stall warning and stall.
We do not need more displays to 'help' pilots in unique situations, situations which first should be identified and avoided.
More displays add mental clutter, demand attention, and increase workload. Pilots need to understand which of the existing instruments are the important parameters and values for the situation.
pretty much exactly the reply when I asked the same question to some of a major aircraft manufacturer’s safety / Test pilot team a few years ago in context if AF447