For the (US) FAA certification, were cost and maintenance complexity the original reasons for the avoidance of designing an accurate indicator in the first generation and later jets etc? Possibly the older generation of pilots from WW2 and Korea preferred what they were familiar with? The T-38 had a fairly good system and could not have been very complex. Of course you could feel a high angle of attack in the short, stubby wings when "rocks" then feel like "bigger rocks".
Our 60's generation jet has them on the right side of the ADI, but there are no accurate markings and no training or limitations for them. A good system would probably have saved hundreds of lives in the US, i.e. New Orleans, DFW and at other places.