Elevators were useful elevators, even if someone had positioned them to impede you. Yes, yes, you found doors locked with combination locks. But those were areas in which someone wanted privacy . I don't mean everything is absolutely arbitrary, like a slider puzzle stuck in a nuclear reactor. Each environment is, in fact, perfectly integrated with the puzzles that reside there.
Nothing has a reason.
Here's an exception, and I'll tell you why it's not a perfect exception. You find an elevator. Some of the machinery has been torn out, so it doesn't quite take you to the right place. The elevator had a use, and now it's harder to use, but of course the BG left himself a way to jigger it into working. You find clues about how to jigger it.