The companies that make the parts for those missiles (not just the mega corp whose badge is on it) are likely only in business because they make the parts for it, and employ 20-200 people with decent pay and full benefits in Corn County, Midwest to do it.
On the surface it looks like enormous waste, it still might be, but understand that the defense budget is primarily a jobs program and basically only thing propping up Americans manufacturing.
This is why it never gets cut, but anyone red or blue. It employs way to many people and in way to many places without much good work. Republicans especially hate welfare, but if you can get people to show up and turn screws, they'll happily "waste" money on them.