I find that with most things aviation based all the tests and exams are all just hoops to jump through. ultimately it's after having gained our licences that our experience starts to build and continuing the good habits and structure gained in our training is vital in order to remain safe up there.
obviously understanding is paramount with the atpl theory but the exam structure is begging for rote learning. as students we do what we have to in order to pass the exams first time with a high mark. as professionals and pilots it is our responsibility to refresh our understanding by continual reference back to the books (the expressions, "if you don't know it, look it up" and "know where to look it up" come to mind).
personally i dont have the experience yet to comment on whether airmanship has declined over any period of time as i am practically fresh from the training factory but having also recently completed my fic and started work as an instructor i have been amazed over the last 4 months how much i had forgotten / didnt know well enough in order to teach it. try standing up in front of a room of instructors and giving a long theory briefing and you'll soon identify the weak areas in your own knowledge.
ultimately though it is always going to be a steep learning curve and typically with me anyways, something new goes in one ear and something old falls out the other. so yes, having to pick up the books regularly just to recap and touch up knowledge is now a continual process...one which i dont see and dont want to end for at least the next 40years.
all the best,