It's really surprising we've never seen another like it in the archaeological record. This is can't be the first thing of this nature that this craftsman ever made.
We just don't know how much has been lost due to decay or re-melting stuff. I mean just look around and see how much stuff from, say, 500 years ago is still around. Tools and household items, I mean. It's limited to a few museum pieces. And if you look at some big upheavals / iconoclasms (always wanted to use that word) from recent years in for example the middle east, or the cultural revolution in China, a lot of these historical collections end up destroyed or lost for one reason or another. I mean some people were doing book burnings in the US not long ago.