My guess is this is all about the love of the work. It's literally a production of quality and there's no way your going to get it's true worth reflected in it's price.
The text says early Jomon period (so Japans pre-history say 10,000BC) and Ishikawa Prefecture Buried Cultural Properties Center so probably something found in an archaeology dig. I guess it is part of a plate or bowl.
This is a really interesting video - I'm surprised there hasn't been more comment. The first 5 or 6 minutes are a bit generic, but after this, the portrayal of the manufacturing techniques is truly fascinating.
