At 44 years old, and coming up with Commodore's in the 80's, and then my first 286 PC in '87, then having worked in some aspect of IT/IS since '92 I've seen it a bit of what makattak is talking about .
First there were a lot of older workers early in my career who struggled with computers. Understandable. I did about as much "functional" support as I did actual break-fix/technical. Then as it got into the late 90's and early 2000's, it became kind of a PITA, because break-fix and troubleshooting work went way up. When someone called, you knew it was because they had some problem out of the ordinary. Now in the 2010's to 20-teens, it's fallen back a bit, and I do run into more younger users having functional problems, where they just don't know how to do XYZ, and there's no actual "problem", they've plugged something in wrong, or had something turned off. Or that they do something in a completely Rube Goldberg fashion, when there's a quick easy way to do something you thought everyone knew.
It's not a HUGE gap, but just enough that you notice it.
I don't know that it's so much an iOS interface that "dumbed them down a bit" but suspect it's more to do with the advent of later versions of Windows, late Xp and 7 where it was actually reliable, and you could have long stretches of uninterrupted use without needing any configuring or troubleshooting.
What I do notice is that when it's a "simple" functional support problem and not a troubleshooting issue, the younger people who had that problem don't ever repeat it.