Capt Eather was good at a number of things but, by all accounts, flying fast slippery big jets was not one of them. He was a black belt in judo and a good teacher of same by all accounts.
The advent of the CV880 frightened the bejesus out of a number of the older brigade who had progressed from DC3 to DC4/6/6B and Electra.
As a consequence they were too worried about their own competence to be able to manage monitoring someone else doing a sector, assuming, normally wrongly, that the F/O probably had the same tenuous grip on things that they themselves had.
There were only a very few that didn't give away every second sector. It was no act of defiance against the company as stated earlier in this thread but simply a manifestation of insecurity.
As an historical footnote, Capt Eather's last flight in the company on the 707 involved a rather sweaty RTO on Rwy13.