You'll never come close to getting the visibility that you can with a backup camera. With a decent backup camera the only blind spots are actually underneath the car itself. You can't possibly match that without a camera on anything other than a motorcycle. Setting the legal requirement of visibility without mandating a camera would either make it completely impractical to avoid a camera or you'd be sacrificing visibility by making the mandate achievable with only mirrors and windows.

> Legally mandating the expensive gadget-based way of doing things seems horribly shortsighted.

Your perspective is biased. If the backup camera had been invented before you were born and the automobile after you had been born than you would consider it only logical and familiar to see backup cameras on the wagons and horse drawn carts that you were used to but you would consider automobiles to be 'the expensive gadget-based way of doing things [that] seems horribly shortsighted.'

If backup cameras weren't expensive gadgets then I wouldn't consider them expensive gadgets, sure. But they are, so I do. When the facts change, I change my mind; what do you do?