Is This Unusual?

I don't think that it is overpriced at all. It has had a SOLID backing of demand for an entire century now, and it always will be in demand. It's symbolic of our hobby, the king key date of the most collected coin ever, and even many non-collectors know about the "s-vdb". Though it's not rare, the demand still far outstrips the supply, and the price will always be high since everyone needs it to complete there set. There are also a multitude of "key-date only" collectors, and this coin is a requirement for a US key date collection.