My point above is that to call something 3D graphics does not depend on having per-pixel correct visibility and painter's algorithm (and others) is a valid meth

My point above is that to call something 3D graphics does not depend on having per-pixel correct visibility and painter's algorithm (and others) is a valid method to render 3D graphics and was for many years. Applications using it either accepted the limitation (many games did that) or tried to overcome it by preprocessing the geometry to create clusters that are unlikely to overlap or by performing subdivision on the projected polygons.