Quantity has a quality all of it own, and all that.
Ukraine is doing wonders managing tons of different producers and models, but Russia production capabilities have always been a problem.
Ukraine was in the lead with their interceptor drone. Unfortunately now russia has refined their drones to not be multiple pieces sticked together, and has added small jet engines.
The new drones are both too fast for interceptor drones and might even survive a hit thanks to the body made from a single sheet of metal.
Now the new russia drones cost about double, but intercepted rate went down from 90+% to about 55%. Math says the new drones are more than paying for themselves.
But for mass producing a solid design, 3D printing is the worst solution, because it is slow. Injection molding would be the fast (and cheap) way.
You're still thinking like it's 1990
So yeah, if you have special needs, modifying a special ops drone, or simple part printing, they are great.
Or like I said, distributed manufactoring.
~10 years ago I was really into designing my own "drones" (but the kind that don't kill people) and I primarily used a CNC machine (Shapeoko 3).
Multirotor vehicles are a good match for designs that are a series of mostly flat plates connected via simple standoffs and you can knock those out really quick with a CNC machine.
Injection molding is certainly much better than 3D printing for scale, but CNC is a nice middle ground that allows for quick manufacture while still having a lot of the same flexibility for iterative design that you get with 3D printing.
Laser cutters and waterjets are CNC machines.
And yeah they are generally faster than using a drill, but cheaper is situation specific (can be, depending upon the scale).
We still require logistics to transport the drones into effective range, intelligence to know the most effective targets, and military grade wireless communications to guide the drones.
If the intelligence is good enough long range missiles can kinetically disable drone production or drone stockpiles.
Slight spoiler:
It's a bit "paperclip maximizer" and a bit "grey goo"
In fact I was skeptical based on the article, but blown away by the paper.
It's a linear motor, more like a speaker voice coil without cone.
it's a linear motor.. like a speaker coil assembly
fig23 shows how a radial assembly could be made