Even in such cases it doesn't prevent you from having perfect shading without any visible pinching by just editing , transferring vertex normals. Nobody used sub-d topology on static meshes in games before. Only on characters. Now it looks like a must for some uncertain reason. Here is an example how with totally "bad"…
No, on both counts! Because you'll find as time goes on, progressively modeling objects of ever increasing complexity will require ngons or n-poles or triangles for certain situations where they're unavoidable not too which is really an efficient process in maintaining an effective edgeflow, that usually mitigates shading…