Three historical documents linked below:-
The first (early 1970s) considers the arguments for changing from 3 crew to 2 (BAC/HSA - British Aerospace). Note the views on crew duties, but also that the considerations were very futuristic. The AFD was evaluated by a range of operators, which proved the concept, but still faced bias and commercial issues before certification acceptance.
Similarly structured arguments would be required for 2 pilots decreasing to 1 during the cruise.
The two other documents relate to the design philosophy’s of Airbus and Boeing aircraft (published 1970/80 ?). A simplistic contrast based on these views suggests that the 1 pilot cruise would be easier to argue for the more future-looking aircraft.
Boeing constrained by the past - ‘man or machine’.
Airbus, freedom of the future - ‘man and machine’.
All of the authors were test pilots - engineers, people with visions of the future.
https://www.dropbox.com/s/21i32mrc5o...09410.pdf?dl=0
https://www.dropbox.com/s/g1vzpdie1z...2B%2B.pdf?dl=0
https://www.dropbox.com/s/91aqr7vy9n...2B%2B.pdf?dl=0