One squadron of F-18s with JDAMs or a flight of GR9s with E-Paveways will do way more damage for much less bucks.
Are you sure about that?
I'd guess that a decent 155mm will deliver cheaper destructive power. Extra range keeps you out of harms way.
155mm gives you savings over the life of the system - with shared development costs and standardisation.
Plus, there is actually a real prospect for overseas orders!