Blame who you want, but the suggestions that you should know exactly where your wing tips are on aircraft of this size are ridiculous.
Most people couldn't tell you where the back end of your Ford Focus is, let alone something which is hundreds of feet away. It's not ignorance or inability, it's one of those irritating human conditions on par with not being able to see through walls.
Can you become familiar enough to make a good estimate? Yes, of course, but it's an impossibility to do it within a few feet.