As one who was a cadet pilot with 250 hours in 1971 on the Boeing 707, one major difference between now and then is that you often had 4 or 5 crewmembers on the flightdeck - Captain, Senior First Officer (who also had a Flight Nav Licence), Flight Engineer and the new Second Officer.
As SO in the first 2 years or so you spent quite a lot of time observing the operation being flown by the two very experienced pilots and the FE and assisting with such tasks as getting the met and jumping in the L/RHS when the a/c was in the cruise especially across the oceans and/or when the Capt or SFO or even FE were taking a break.
Also in those days you had a restricted take off/landing card which was progressively derestricted as you gained more experience and underwent more landing training.
You were mentored by very experienced pilots/engineers and learned much in the process and observed, most of the time, how the operation was professionally run.
Now we give the new pilot a quick MCC course and he is thrown in the RHS on the line and expected to cope with a whole myriad of challenges. In the circumstances, given the environment we now operate in with increased traffic densities, some punishing schedules, the burden of huge bank loans, and the erosion of Ts and Cs I think most of them do a mighty fine job!