This is a completely separate idea that I got from a science fiction story when I was young, seemingly 2 centuries ago. Ever-shrinking machine shops. Use a conventional machine shop to build a smaller machine shop. Use that to build an even smaller machine shop. Etc. An iterative process. Its success requires that mechanical error tolerances become smaller as the machines become smaller.

At present there exist conventional machine shops and nanodevices fabricated on chips. There does not exist anything of in-between size.

Could 3D printers of differing manufacturers and differing design principles, be teamed together to make the next smaller size family of 3D printers? The next smaller size 3D printers need not look the same or even work the same as their larger forbears. They just need to be of practical use. It would be nice if they were complete enough to make even smaller 3D printers.