https://www.tandfonline.com/doi/abs/10.1080/1351804050035499...
Laser guided Excalibur rounds didn't come out until much later, same for the laser guided jdams. And the cost of those is much higher, plus logistical an deployment cost, than a FPV drone.
Edit: I also don't know anybody that ever fired a copperhead round in anger. That was very much a product of 80s and 90s doctrine to counter Russian armor.
You won't find them with light infantry, but you will with Cav / Mech units.
To my knowledge there still isn't a laser guided mortar in the US inventory with dual mode laser terminal guidance. HEGM project was cancelled in 2018.
Local airborne EW platforms can relay GPS signal.
Combined with Inertial Navigation System reduces the CEP.
Laser terminal guidance gets it on point.
The US has a lot of work to do in EW - it also has done a lot of work to prepare for some of these scenarios.
So yeah that is in line with what I have said.
US doctrine is based in air dominance.
Also, most Excalibur rounds do not have laser guidance kits. Those are much newer and more expensive. We may have given Ukraine a handful, if that. Still requires laser designation by airborne or land forces, but can give you excellent accuracy even in completely denied GPS environments.
The artillery, while destructive, is not going to be nearly as accurate. If you want artillery to hit something on the move accurately you want something like a laser adjusted Excalibur round.
The drone is actually extremely efficient.