I'm guessing the reasons why the escalator angles are so steep is because the height between the floors haven't been increased for greater clarity and are not to scale.
I was thinking the same thing, at first I assumed they were all elevators, then I realised they are not quite vertical, just at a very steep angle (speaking of which: what's the steepest angle that is practical for an escalator?). And of course, a station that is served only by elevators is not realistic, it would be a nightmare during peak hours :-D