@arstechnica Haven’t read this one yet, but there’s another book on the subject that I can highly recommend - “Humans to Mars. Fifty Years of Mission Planning, 1950–2000” by David S. F. Portree. It’s available for free on NASA website.
The main thread that goes through the entire book is that the Mars mission planning was constrained mainly by financial considerations and a lack of political support, and not as much by technical considerations.