Yes and no. You are of course right about the economy of scale that injection molding gets you for price per part, but that isn't the whole story is it?

When you are fighting in a highly fluid conditions, setting up production lines that rely on tooling would be really really nice, but that not the operating environment in Ukraine where they need weapons yesterday and can't rely on long logistics trains.

With intermittent power at the front, and the difficulty resupplying anything under fire, a mobile production station like a cheaper 3d printer is the difference between being able to use existing mortar rounds as precision munitions, or needing to spend the fuel, time, and risk of compromise to the logistics convoy and personnel. Trucking in parts from a place with stable electricity, and tooling to produce something cheap and efficiently pales in comparison to the flexibility being able to rapidly iterate and adapt to the changes on the ground gives you.

It's about the right tool for the right application, and there are negatives to additive manufacturing that are outweighed by the positives on the ground. It's so much better to be able to make a small change mid-operation, than needing to redesign and change tooling for a minor but important change.

Right tool, right job, right time. 3d printing is a part of that, but not a solution. Nothing is really.