I'm one of those people who admittedly spend way too much money on keyboards :) I don't have any artesian keycaps, but I have bough aftermarket (?) keycaps that uses plastic of a higher quality. You can tell the difference.
There are also people in the DIY mechanical keyboard market selling circuit boards, plates, cases, etc... Again, it's a really niche market, but people are willing to spend a lot more money at a hobbyist/enthusiast level.
I'm there too, I have 4 $100+ keyboards now, and 1 of them is an "ortholinear" style (keys are in a perfect grid) that I built from a kit and had custom keycaps printed with names of programs on them. With some semi-custom software I use it like a physical "whole computer" shortcut pad.
I now have a button that can launch a terminal window, a button that launches HN, one that does a git pull on all my current projects, etc...
Like you said, it's a niche market, but it's one where most people are happy to pay the higher prices for something more tailored to their needs, and it's a rare "physical" area where a guy in his garage can compete with big companies.
I just recently got a new 3d printer, and I think after I get it more tuned I will be able to print fairly good quality keycaps. If they are good enough, I might try selling custom made-to-order keycaps if there is any interest.
Where can you get custom printing on keycaps? I have an Ergodox but what I really can't get used to (even after 2 years of full time use) is the lack of labeling for the special keys. I've looked for years for ways to do custom printing or labeling but all methods I found suck.
WASDkeyboards offers printed singles in multiple ways. They aren't the best quality (they are UV coated ABS, I used their keycaps on another keyboard and the coating started to wear through after about a year of daily use, the text is still fine though), but they are the king of custom printing right now in my opinion.
You can go to [0] to get just text on a keycap with a fairly easy web-ui to describe the text, position, and size you want it.
Or you can take it entirely into your own hands and go to [1] to give them a vector file that they will custom print on to the keys.
They also offer that service in a "full keyboard set" option [2], so you don't need to do a ton of keys individually if you want to do the whole keyboard (although the full sets most likely won't fit your profile, but they do fit a good number of more standard keyboard layouts)
Again, they aren't the best quality, but they do a good job, and they take care of their customers. Plus the amount of customization you can do is pretty fucking insane. [3] is always my go-to example for just how customizable they are. Not only full color printing, but also individual key plastic color selection.
roel_v just buy some right sized blanks in your profile and use a paint pen to label them, or get some relegendable caps in your profile and make little paper labels.
That or just dump the ergodox when you realize that it's just a pale sad imitation of a kinesis advantage.
There are also people in the DIY mechanical keyboard market selling circuit boards, plates, cases, etc... Again, it's a really niche market, but people are willing to spend a lot more money at a hobbyist/enthusiast level.