Precision munitions still aren't better than your fire direction. Even with undisputed air control, undirected indirect fire is mostly a way to punctuate press releases with explosions, not really a useful tool to attrition enemy formations. Target discrimination from the air is, so far at least, an art form that eludes the ken of human air forces. That *might* change with cheap, low-flying, high camera resolution, high data bandwidth drones. But it hasn't yet. (And probably won't, because people are going to learn how to shoot down drones too, eventually.)
Vehicles are more vulnerable than infantry and static positions, because they can neither hide nor dig in as well. But even vehicle casualties to undirected bombardment have proven lackluster and overhyped in a lot of historical conflicts where the defenders' archives have been opened to researchers. Turns out people who like launching undirected indirect bombardments often replicate their bad target identification in memoirs and after action reports, leading to exaggerated claims of effectiveness (and undercounted collateral damage). And for various institutional reasons the claims made by air forces about their operations tend to be given more air time and credence than the claims made by their victims.
Undirected indirect fire is really useful for blowing up oil and gas infrastructure. But oil and gas infra is, ah, temperamental at the best of times, and will blow up without much provocation.
In related notes, artillery (and orbital bombardment and CAS, both of which are really just expensive artillery) should probably have an efficiency bonus when used in an infantry support or counterbattery roles and an efficiency malus when not used in a combined arms role with infantry.