[vurpo]

As unintuitive as it may seem, 3D printers are actually way simpler to DIY than 2D paper printers. An almost modern 3D printer could have been put together by a hacker in their basement in the 90s. The only reasons they didn't trend until the 2010s is that patents prevented them from being commercially possible until the 2010s, and then it's taken hobbyists many years to gather the knowledge about what to do and not to do. The mechanical construction is not complicated, and the necessary components and materials have been around and readily available for decades.

2D paper printers, on the other hand, are way more complicated and require specialized components that make it very unlikely for anyone to be able to DIY a working laser or ink jet printer. If you want a "free" paper printer, then a much more viable alternative is to hack a "closed" printer to work as you want. With 3D printers, if you want a "free" printer the most viable alternative is actually the opposite: you can just build one yourself since the construction is so simple.