You're wrong. There are massive 3D printing farms that are producing consumer products at scale in the united states now, and that is a direct result of the work that the maker community (both here and especially in China) has done on 3D printing.
Most of the things you are going to touch today are going to be injection-molded. Keyboards, keychains, car parts, cups, computer cases, etc.
There's a 3d print shop that sells at my local farmer's market. But they only sell tchotchkes. I am imagining a world where the same size business could also phone cases or mugs or even supply a local manufacturer.
We've been at the very beginning of what you're describing for about 3-4 years now. I only started selling by request of the communities I'm part of because none of them knew anyone to print it.
Haha! Doing the Lord's work.
Although, it should be noted that while I buy lots of hard to find car parts this way, as a buyer I almost universally prefer actual molded plastic parts in almost every situation. In some cases I have even requested my money back because the seller deceitfully tried to make their parts look OEM.
I've actually started recommending alternative parts that operate the same, but came from different machines, or even competing manufacturers (like a Suzuki brake cable guide that bolts directly on to a Yamaha but looks nothing like the original).
In the end, this is a product of my frustrations with obsolete parts that become impossible to find. I'm also trying to stay cheaper than the OEM costs of 5 years ago to promote my alternatives ending up on machines that see dirt and rocks on the regular while NOS parts are more likely to end up on pristine restorations. Buying NOS parts for some rough examples never sat well.
There's a (non-critical) switch for my 2000 Honda Foreman that I can't find anywhere except direct from Honda or a dealer and I don't think it's worth the $100+ they want from it. For other model years, I can find it from $20 - $60 which is more reasonable.
I've been thinking of making my own for a while but now you have me thinking of making them for resale. I can't be the only person in this situation.
I'm selling a pair of brake cable guides for $10 including shipping to the lower 48. I'll make more money if I find a cheaper way to ship, but I'm not really doing it to make money.