JDAM's are a lot cheaper. They are a guidance kit bolted on to a MK-82 gravity bomb. There are a lot of MK-82's in stock, as they have been made since the 1940's.
Problem is you put a crew and an expensive airplane at risk.
We are out of missiles because the current administration wants to minimize combat losses. Looking at the dollar cost; it seems like a bad idea. But is this war worth any of our soldiers / sailors / airman ? (no)
Also, you can jam JDAM (GPS) guidance. The Russians are masters at jamming and I'm fairly confident they've shared some systems with Iran.