So the readability of Microsoft’s and Apple’s code is low, or the code is readable, but the quality is low? What are you trying to say? That readability is not the key component to maintainability?
I find that the majority of coders are so use to using tools and frameworks to build their stuff that they think they have to design like the very generic tools they use when in fact all they need is very specific and targeted code to achieve their goals. Problem is that most of them do not really understand memory management, call stacks, and threads and their convoluted code reflects it.
Back in the old C days is was a game to be as cryptic as possible now the style is to try and lay in as many levels of base classes and interfaces as you can with no real gain.
I’m saying I’d rather write prose than code anyway.