Telephones and computers come apart just fine! The tools and techniques involved might be different, but there's plenty to learn with prying apart a mobile device.
While there is plenty to learn, I think there is a difference for a kid taking apart a modern LED TV versus an old CRT, or an old computer versus an iPad.
The concepts used to operate a CRT or VCR or even an older computer would have been easier for me to figure out and poke and prod as a child than newer devices which operate on microscopic scales with everything integrated. I would think a child today would need much more background and reading before they could begin to comprehend what's happening in an iPad versus looking at something that moves, and manipulating it to see what happens. Or at least test things with a multimeter.
I think it's fundamentally the same today as it has ever been, just operating at a different level of abstraction. Once upon a time, making a screw or a nail was a significant undertaking. Now it's something you buy at the hardware store for, quite literally, a dime a dozen. Nowadays the abstraction level has moved up from nails and screws to CPUs and SOCs, but you can still obtain components and assemble them into something that is greater than the sum of its parts. Turning a RasbPi into a DIY laptop with a keyboard, external storage, and display is a project well within the reach of a child today and every bit as worthwhile as futzing with the gears in a mechanical clock. IMHO.
The base requirements are higher to get into tinkering, which reduces the probability of a child tinkering (my conjecture). Although, perhaps that’s mitigated with the increased ease of accessing that info online.
For example, I could take apart a VCR with a couple basic tools and no input from my parents (who were always busy working and didn’t know English). But I might have needed some guidance on where to get started with a Raspberry Pi and obtaining one, guidance I never would have received from my family.
