Then I got her an iPad - the very first one, back when they were released. She absolutely loves the form factor, but hates the UI, and finds it inconsistent, having to learn every app on its own. You could say that this is partly because of having to re-learn - except that it's been several years of nearly exclusively using iPad and iPhone for all her needs, and she still finds it terribly inconsistent.
A lot of capable people are mathphobic, and it's strange to watch (as someone who took naturally to math). The expressions on the page (or the attempt to produce those expressions from a model in their mind) causes them to seize up. It's like watching an anxiety attack happen. Something about math (the subject, their experience when taking the courses, whatever) has left them with a severe discomfort or level of fear when dealing with it.
Computers illicit the same response from many people, regardless of background, education, level of experience with computers. They develop an understanding by rote, or with a rudimentary (but likely totally wrong) mental model. As soon as something is slightly different, the fear or discomfort rises and their mind blanks. They cannot figure out the next step. At an extreme, a color changes and they think it must mean something, but really it's just that that control is now "transparent" (pulling in the background color but blurred) and they happen to have a bright red object behind it, when normally it's a more neutral gray or blue. For some it's that things are no longer in the right place or that display differently (think of the changes in the Windows start menu over the decades). They'll have different thresholds, but once they hit theirs they cannot proceed without great difficulty.
Of course, any attempt to improve math education gets screamed at ("New Math! Common Core! Blah!") and the whole thing just becomes political.
Another problem is that the discovery learning approach can lead to some horrible failure modes for math. I've seen cases where an hour of proper instruction can go further than a whole term of trying to see if they can find it out for themselves. Case in point: the rule of three. If 10 apples cost $20, then 5 apples cost ___? You can spend ages thinking about what it "means", or you can learn that you write down a 2x2 table, multiply across the diagonal and divide by the number in the corner.
given enough time to read and debug, I suspect I could eventually figure out how any piece of code worked. but if you give me a book and ask me to pick a good topic for an essay, I might not finish before the end of time.
I agree it's normal and expected that people get used to buttons being in certain places, and moving them around too often is bad usability.
That said, the fact some of my elderly relatives use and understand technology this way, by memorizing how many centimeters from the edge of the screen they should look for a button, makes life needlessly tough for them.
They'd be better off understanding what a button is conceptually, what forms it comes in (e.g. standard button vs. underlined link with no outline, etc), and how buttons might be grouped.
I know it's a lot to ask of elderly users, but it pays dividends.
After many years of Q&A with me, my mom understands her iPad conceptually and as a result gets much more from it than my aunt does, who only understands procedurally that if she presses her finger on 'the button in the corner' then 'x' should happen.
If there is no button in the corner, my aunt is lost.