I think 3D printing is overrated. If you have a mold shop and an injection molding machine, you can get a mold made in emergency mode within 24 hours (yes, its possible). Optimization can take another 24 hours and some blank shots. If you don't care about aesthetics, you can do it much, much quicker. Then, its 20 seconds per part for next 300,000 parts for dirt cheap. Raw polymers can be sourced rapidly as there is a very strong supply chain around the world.

3D printing said it will change the world in 2011. Then it said it will revolutionize manufacturing in 2015. Its 2020 and it didn't happen. Injection molding is not going anywhere. SLA litho has nicer quality parts but take exceedingly long to print and more importantly - clean/UV bake takes a long time to cure.

One area where 3D printing is actually useful is to be able to print parts that would be impossible to manufacture using injection molding - that cost to benefit ratio must be evaluated and questioned - do we really need a part like this? Perhaps its a dental implant, etc. Then it's justified.