Fear and naivete are powerful motivators, catalyzing these early innovations. More often the realities of budget, politics, and competing priorities hampers the same creative energies.
If there wasn't a more compelling reason for higher taxes on those who can pay more should... It just goes to show that there's always someone dumb with more money than they know what to do with that's willing to dump it into making more people dumb.
Mimeograph aka spirit duplicator used a stencil that you could write on or type on and then use alcohol to then dissolve the raised part of the stencil and transfer it onto the paper. It worked well for simple stuff but kinda poorly for halftones and could prob only provide 300 copies before you'd need a new stencil.
Xerographic from Greek "dry writing" differs in that you use a fine powder (toner) that can be electrostatically charged and then drawn to paper using a light-sensitive drum.
The genius of the AM machine is that it could be used to print on practically any medium including metal, dogtags were printed in this way. Also, data could be saved in either punchcard format or later electronically. The last big use was for imprinting credit cards.
All that was needed to make a Selectric into a terminal was essentially a box to take the electrical signals of hitting the keys (that triggered the correct letter on the ball to strike the ribbon) and amplify/send them to an interface into a device that could take TTY. Early word-processors and cold-type machines used this since those Selectrics were ubiquitous and dang durable.
