Ukraine has manufacturing capacity for (ten?) millions of drones per year and manufactures millions of drones per year because they are using millions of drone per year.

The problem is continuously maintaining, and upgrading that sort of capacity when you don't have an active war that requires it.

It's a very different model to traditional exquisite weapons. It makes no sense to actually buy and store the drones as they quickly become obsolete. But someone needs to pay for the capacity to be maintained/upgraded. Dual-use can help, but only partially