Production is always judged by how much time it takes for raw material to become finished parts. Additionally that is split between 'operator time' (person required) and 'machine time' (just the machine running).

'Operator time' is a function of how skilled the operator has to be (machinists cost a lot more than technicians).

'Machine time' is a function of operating cost and depreciation.

So anything that shortens those times, or cuts those costs lowers the cost per part. Parts "have" to cost less than a threshold amount to meet the sales price of the final assembly + margin.

That is all basic manufacturing. The key is that costs have typically been reached by doing things in volume with 'tooling' (investing in dies and jigs to configure the machine to easily make the one part). That essentially makes the production line 'single use' while it is tooled that way.

These guys are proposing that they can make metal parts at the same cost as the tool and die folks in smaller quantity and with no setup costs. That changes several things;

1) You can make warranty/repair parts "on demand" so cut the cost of making a million widgets and storing them in a warehouse.

2) You can make 'small runs' of products for more specialized markets at a price that the market will accept.

3) You can support more variations of a given product without your spare parts inventory exploding.

4) Production can be parallelized from small scale shops so a large 'mega factory' isn't needed, instead you can get a dozen shops with this gear to work in parallel to meet your production target.

If they can pull it off, it really does change a lot. If they can get the costs down further it opens the possibility of domestic delivery of parts from a certified vendor rather than a warehouse somewhere.