For smaller parts that most people would be printing, the tools don't cost that much. For a simple part you might be able to get a tool down to as low as $20k, but there again that is still a lot more than most 3d printers. Hell, we have molds that are 4" square and are pretty cheap. We do a lot of very small precision components.

The variables in printing, material properties, and production speed are critical. Typically we are only using smaller format printers for prototyping or one off parts, with exceptions being in exotic geometry that can't be otherwise made. If a typical print time is 2 inches of height per hour for an average cross sectional area, and your part is 4 inches tall, then you can do around 4200 parts a year if you run 24 hours except holidays.

For a $100,000 printer, that's around $24 a part for a 1 year ROI on the machine, not including materials, design, setup, and electricity cost. Production rarely justifies that price and speed for a plastic component. You could see a part being $30 if you only run that all year, up to $50+ per part for high buck materials with long print times or larger volumes.

Companies are looking, that's for sure, but we aren't there yet. The machine costs need to come down significantly. Even if you stretch it out to a 2 year ROI, which many people hate doing, you still have pretty expensive parts. For prototyping however, even a $50 print is WELL worth the cost to test the design out for fit and function, make changes, print it again, repeat that 5 times... then move forward to a production injection mold, or in some cases start building the fixtures for production machining that could cost thousands.