Frankly, and this may just be cynicism, I speculate that these hidden functions are a way for Apple to hold consumers hostage to their platform. If someone spends a few years learning all the idiosyncrasies of OS X and iOS, they may be too intimidated to switch to another platform, since they've invested so much time into learning Apple's OS.
I suspect it's more that you're becoming a power user. Power users have always had a lot more functionality available at their fingertips, in exchange for investing time learning a platform really well. It's just market segmentation: you don't have room to put all the functionality that everyone might need on screen, so you put the stuff that most people need all the time on screen, get them hooked, and hide other stuff in an obscure reference manual so it can spread through tips & tricks blogs.
Example of a good feature to hide behind "hold option": removing the "..." from "Sleep...", "Shut Down...", etc. in the apple menu, meaning that selecting them won't prompt you before executing the command.
Example of a bad feature to hide behind "hold option": clicking the green window button to maximize instead of going to full screen.
*Especially on recent versions of MacOS, where fullscreening an app moves it to a different desktop.
Whether on purpose or not, it's definitely a form of switching costs. It's the same reason I stay on windows. Though windows 8 changed so many things I basically had to learn all over again. I can't do basic tasks at times and have to Google instructions for how to do them. Simply because they changed the interface.
My theory has always been that Apple liked the design aesthetic of a single mouse button and and aesthetic won out over actually good design. From my experience this is the Apple way.
I came to this conclusion after buying my first Mac about 10 years ago. It had a corded mouse which plugged into the keyboard. A nice aesthetic, though I questioned a corded mouse on a $1500 desktop in 2006. Upon my first navigation across the screen, it was apparent that the cord on the mouse was too small to cover the area of the screen. Very poor design, but the shorter cable didn't leave a mess of cable on the desk. Good aesthetic, bad design.
It was done to force developers to expose actions through the menu bar and thus be consistently discoverable to the user.
Apple is and has always been about a tiered learning curve for their devices and I think your point about the mouse is a great example. If you put 2 buttons on a mouse, it complicates every interface element by two-fold. Every item that can be clicked can now also be clicked with a 2nd button. For a brand new user, keeping 1 button basically forces them to look at what's on the screen and assess what they're doing rather than needlessly right click everywhere searching for a context menu. People who tend to right click on things (when they understand what a right click does and intentionally perform the action know what they expect to be behind that right click.
I feel like iOS is the same way, and intentionally so. A novice user can get by doing all of the basic commands with swipes, pinches, and taps. A more advanced user can do rotations, shakes, and multi-touch swipes. An expert user can access every feature of every application.
It's very poor design.
No, it's Windows/Linux-bias on your part. In the old time, every (and I mean every) medium-level Mac user knew that you can unlock a lot of additional functionality with the option-key. People today just seem to assume the Mac UI is built on the absolute same principles as the Windows UI, which is not true.
Quelle horror!
maybe this is showing my age, but that came relatively late in the history of Mac OS
But I otherwise agree and do like the approach of basic/necessary UI as simple as possible, optional/advanced UI gracefully hidden