3D printing has been touted for several years now as a "disruptive" technology, especially for things like wargaming, but it is still a new technology with shortcomings.
Print on demand is actually quite expensive and the cost hasn't really come down.
The fan sculpts that I see are based on very high quality 3D prints that are then cast in metal, but I believe those prints are very expensive and I do not know where they come from.