To me it does not look strange. These missiles are very advanced electro-mechanical-optical systems with a lot of R&D behind it, and that is what you pay for. Also factor in the fact that they work for government contracts, which are usually significant more costly. You may wish that the request to tender from the Government includes "as cheap as possible", but usually it is the opposite.Get a similar figure just from $264 million contract to Raytheon to produce 571 missiles = $462,346 per missile.
But again, something feels off looking at it like that.