"One of the keys to how all this worked was the PARC version of Catch-22, known as "Error-33". One committed Error-33 by putting any externally controlled system, in-house or out, on one's critical path. This included vendors. Error-33 was avoided by doing all that was necessary within a research group and then sharing. Thus, virtually all the PARC hardware — including two big time-sharing main frames, the Altos, Ethernet, Laserprinter, file storage, and the systems that followed — and software — including operating systems, programming languages and development systems, productivity tools, etc. — were completely built inhouse by these few dozen researchers.
This sounds disastrous, but there is an important collection of theories in which the 1st order version and the 2nd order version are completely different yet both are true. For example, in programming there is a wide-spread 1st order theory that one shouldn't build one's own tools, languages, and especially operating systems. This is true—an incredible amount of time and energy has gone down these ratholes. On the 2nd hand, if you can build your own tools, languages and operating systems, then you absolutely should because the leverage that can be obtained (and often the time not wasted in trying to fix other people's not quite right tools) can be incredible."