Does it take an hour to wind a coil? Probably not. At worst, a minute for an experienced worker. That gets you to 130'000 $ per hour and 0.13$ human cost per device. Though a minute is very optimistic, you don't need that many windings, if you get it down to 10 seconds, which is a lot of time to wind a coil, you pay 22'000$ and 0.02$ per product.

That's fairly cheap and if a robot can do it for less becomes questionable because robots need a lot of maintenance and cost a lot.

What if you want 100 billion an hour?

Then you're screwed no matter what process you use. 100 billion 1 gramme devices is 100,000 tonnes. Per hour.

For reference, that's about half the discharge rate of the Rio Grande.