My idea is to force the 50 year old designs to meet the new standards or be discontinued as is done in the auto world. Your point about cost would normally be true, but the current pricing outside the normal demand curve.
Let’s say we demand more robust fuel lines, better stall behavior, and better impact performance. Something like an SR20 or DA40 or M20 might adapt easily while the Skyhawk and Archer might require so much upgrades they no longer compete. Volume helps the survivors reduce costs unless the other players respond with better designs.
The average price might rise a little, but the image of the entire industry would eventually improve and attract more participants. My problem as a leaseback owner was not my purchase price so much as lack of volume. Take away the sheer numbers dominance of the Skyhawk and my price would have been the same as the $30k less Skyhawk. My insurance would likely have gotten lower than theirs.