Database sounds like a good idea. But when it grows the database needs lots of ressources (memory) which means money (as you said). So it would be tempting for the admins to monetarize it similar to Google, or?
I would love to read a wiki about degoogling phones. I am confused about rooting, changing the bootloader, custom ROMs, libre OS ontop of Android, etc.
I am still in the claws of Google. I use shitty Android (which is better than Apple). I use a Gmail account (and a self-run mail account). I use Chromium, but plan to pick a more lightweight, libre browser. I also plan to buy a Ubuntu Touch capable phone. [Edit: I use Duckduckgo.]
I don't feel too bad about being dependent of Google because I'm optimistic to replace it step by step.
I also had the idea of a federated search engine, but I have other stuff with higher priority.
For moving probably the solution: 2 step motors (1 horizontally, 1 vertically)
I don't know of any patent that is on basic printers. If PDF is patented: You could convert PDF and PS files on the computer and then send the raw pixel data to the printer.
Fingerprints: I think you mean the yellow dots. I guess they are totally voluntary by the industry. (If any expert reads this and know that's wrong, please correct me.)
Again guessing: Ink doesn't produce poisonous stuff, only laser and thermo printers do. Or?
Regarding re-use of existing cartridge design/system: would it be too hard to 3D-print a cartridge in our own format?
Also we need a very primitive CPU/processor/microcontroller and a very simple firmware. Just spray ink or not, then move the carriage horizontally, then vertically.
I am wondering about (a) the data cable and (b) the power source:
MMIX is created by Prof. Knuth purely for expressing his algorithms. Back then C++ and Java were the latest, hottest sh... (and would soon be outdated themselves). Prof. Knuth didn't like C++ and general programming language fashion. So he invented MMIX. It was never meant to be implemented in real HW.
I don't know whst's wrong with the other CPU architectures you listed. I especially wonder why Sparc wasn't used more.
If the ecological costs would exist as financial costs for the companies, that would help a lot. Right now it is cheap to throw away poisonous waste, ship stuff from far away countries etc.
And I think you hit an important point when you said that the average consumer doesn't reflect much.
I like your idea. I wish I had a good idea how to start it small. Because, look at Wikipedia, it started as a small idea and look at it now!