Ignition Override,
Unfortunately, there is no simple answer to your (quite reasonable) concerns.
Fifty or sixty years ago in the DC3 era, the pilot could pretty well know just about everything there was to know about the aircraft and the flying thing .. the aircraft was simple, the systems were simple, and the flying was a largely skill based activity with the overriding considerations of commonsense airmanship ...
Now the aircraft are far more complex in construction, the designers and software developers can't get the code right all the time, and airways procedures in their interaction with the FMSs etc., has taken much of the fun out of everything .. now, it is just NOT possible for the hardest working pilot to know more than a subset of the total story ..
Much the same as comparing academia in the middle ages and now ..
The ATPL standards vary around the world but, especially for the more involved and intensive jurisdictions, getting that pass is no mean feat .. not so much that the work is difficult .. more that the comparatively high pass mark without consideration makes for a degree of difficulty .. not like many of the university courses which (being far more logical) argue that the notional standard of students doesn't vary all that much .. ergo there is a reasonable argument that the spread of results year to year ought to be roughly similar .. which, then, suggests that variability in results is associated with variability in examination difficulty ...
This, in turn, leads to the well-known academic principle called the "zero shifting theorem" which sees raw data marks mapped to something more representative of the norm .. one still sees the ranking preserved but the marks, at the end of the day, are a bit arbitrary.
In the airline world, often the pragmatic training school takes the view that the student on Type Conversion needs to get the basics well established but doesn't need to be exposed to silly pedantry in examination "standards" .. far better to give him/her the basics and let the fails and passes fall as they will during sim or line training .. ie emphasising the practical but still requiring the underlying knowledge basics. I recall one tale for a 727 endorsement .. the company chief pilot was a student and the school set him up for one exam .. which, in fact, was two exams .. one for him .. and one for the rest .. apparently he became a tad anxious as student after student completed the paper and he was stretched to the limit with his "tailored" questions .. so there is room still for a touch of humour here and there.
In the GA world one sees a very wide range of endorsement standards .. one of the most detailed and searching endorsements I have done was for the PA31 many years ago .. at the other end I have been signed off after a circuit or two (admittedly the endorsing pilot knew my capabilities from other aircraft) .. that's the way it goes to some extent.
I fear that there is an undercurrent in the Industry which favours the view that, with increasing reliability and computer driven redundancy, the need for the pilot to be expert in the basics ... is reduced. As a wise man once suggested to me .. that's all fine and beaut .. until the battery goes flat and the widget screens go blank.
Right or wrong .. I am an unashamed dinosaur .. I LIKE the idea of being able to pole a bird around a real tight circuit (I recall a Commander 685 owner for whom I did some design work years ago .. we traded a few hours on his bird for the work .. he was a little surprised when the first couple of circuits didn't go outside the not very big airfield boundary .. I thought it all great fun) ... handfly a raw data ILS to a 0/0 full stop landing in the box .. and so on.
The other (and equally important) side of the coin is that we also need to know the gee-whizz things on our bird and all the other operationally important procedural things .. as well. Just a pity that it is getting harder and harder to find the time to learn as much as we really need to learn ...
The end result is the training and learning workload on the new pilot in an ideal world is growing at an ever increasing rate .. a pity that many opt out and go just for the basics of the need to know syndrome .. this, I suggest, eventually shows up in the differences between the Sioux City outcome (for instance) and the many other accidents where the crews were at a lower standard on the expertise and competence scale ...