1972 Unix V2 "Beta" Resurrected

I once saw a talk from Brian Kernighan who made a joke about how in three weeks Ken Thompson wrote a text editor, the B compiler, and the skeleton for managing input/output files, which turned out to be UNIX. The joke was that nowadays we're a bit less efficient :-D

I’m wondering what the process was for the early UNIX developers to attain this level of productivity.

Did they treat this as a 9-5 effort, or did they go into a “goblin mode” just to get it done while neglecting other aspects of their lives?

A big one is the lack of peer reviews and processes, including team meetings, that would slow them down. No PM, no UX, just yourself and the keyboard with some goals in mind. No OKRs or tickets to close.

It's a bit like any early industry, from cars to airplanes to trains. Earlier models were made by a select few people, and there was several versions until today where GM and Ford have thousands of people involved in designing a single car iteration.