Sure, they were used by the same people with the same habits over a long period of time. The image illustrates what I meant in my earlier, hurried response. Each time the piece is placed or removed from this position, there is a small amount of friction between it and the dish edge and a minute amount of silver is worn away, over time that adds up.
I used this fork to show that the same happens to the tines, the shortened outside left tine is caused by it being the leading tine to touch the dish each time a forkful is taken (by a right hander).
Hope this helps.
Regards, Tom

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