You started with logic gates. How much EE did you do, or the actual physics that makes the transistor possible? Those are the previous (deeper) levels that people had to know before they got abstracted away.
Did I end up an expert at those layers? Of course not, but I know the basics and I know enough that if I need to I know where to start learning more. Just like I wasn't a C++ or hard realtime expert after university either, but now a decade and a half later I am pretty good at those (and a bunch of other skills that ended up relevant to my line of work).
Basically, none of the layers are "magic" to me. Even if I don't know the details of it, I know the general principle and I know I could learn more if I need it.
(I think you naturally end up an expert at the layer(s) you work in, and the knowledge tapers off as you go down (or up) the stack. For example, I know a fair bit about how the CPU works (cache coherency, pipeline stalls etc), I can passably read x86 assembly, etc. Because they affect the layer I work at (hard realtime systems C++ and now also Rust). I know far less about web dev than hardware.)
I think the last time people knew how things were made was in preindustrial societies because they had to build everything themselves (whatever little things they had)
But a core part of the engineer or scientist mindset is curiosity for the sake of curiosity. Just the fact that I don't know something is enough reason for me to poke at it or otherwise learn more. Same reason I still take apart broken electronics as an adult and try to find the fault (and sometimes even repair it).
By the way, mining silicon is particularly easy: it's basically sand. The difficult part is purifying it, especially to the levels needed for modern nm scale chips.
A more useful question than making high end silicon would be: could you with reasonable tooling reproduce basic electric components? I'm talking things like light bulbs, resistors, generators, perhaps capacitors even? Just the basics crappy versions, not modern highly optimised surface mount components. And I think the anwer is yes (for me personally) if I had access to metal wire and sheet stock and industrial revolution era tools.
Did I do all physics or all electronic circuit design or all software stacks? Definitely not. But I spent 3 years learning (and building) about lots of stuff.
The first two years were shared with Electrical Engineering. The second two years started to specialize towards Computer Engineering topics.
* Physics and chemistry.
* Circuits.
* Transistors.
* Logic gates.
* FPGAs.
* Assembly.
* Compilers.
* CPU and hardware design.
* Operating systems.
* Networking layers.
* Programming languages.
* Computer graphics.
Did I master all of the above - absolutely not. I loved some of them, struggled with others. Generally the cut-off for how my brain works is logic gates, I was never strong at the levels below that.
But we did cover them, and I could honestly say I had at least a rough understanding and mental map of everything that happens inside a computer from the point where it's plugged into an outlet, to the point where pixels show up on the screen.
As someone with an EE degree, in first year studies we had physics classes on quantum topics that talked about electron tunnelling and its applicability to transistors: