> It made me realize just how many fundamental things that I completely took for granted in the "modern" computing world, were ultimately just concepts derived from UNIX
Oh so very much yes.
And the flipside of this is that it's very very hard to get new ideas into the heads of people who only know and have only ever seen computers running Unix-style or Unix-inspired computers.
Some examples:
The product that the inventors of Unix did next was Plan 9. It's still alive and in development. Some things that Plan 9 takes as givens that blow Unix folks' minds:
* There is no one true view of the filesystem. It's all namespaces and every process can (and normally would) see a different namespace. They are all correct and there is no one valid underlying view: it's all relative, and all interpreted.
* Everything really is a file. For example the contents of a window on screen is a file. Arguably if your GUI doesn't do this, is it really Unix-like?
* There's no keyboard-driven command-line editing because of course your computer has a graphical screen and you can just use the mouse. Why would you pretend your input window is a 1970s 80x25 text terminal? What's the point of that?
Then Plan 9 evolved into Inferno. It breaks more assumptions.
* C is not low level any more because computers have evolved very far away from the machines C was designed for. C has no native standard build-in way to represent matrices of 256-bit values and apply SIMD transformations to them as one operation, and no way to farm out 10000 threads to 1000 compute units.
So, throw C in the bin, and replace it with something a bit more abstract.
* Computers have different types of CPUs. So, compile source± to intermediate code and embed the runtime in the kernel. No need for a JVM or any other runtime; no need for WASM or eBPF; it's stock.
* Any binary can execute on any CPU. Computers can have more than one type of CPU and compiled code can move between them without translation.
Or to move further afield...
* The Unix tradition puts the filesystem at the centre of the design. Not all do. So some OS designs do not have filesystems and do not have the concept of files. It's objects all the way down.
* Some OSes and some languages don't have compilers or interpreters or binaries. That's a 1970s implementation detail and it was eliminated 50+ years ago.
This kind of stuff can be much more powerful than the Unix model, but folks reared on Unix dismiss these ideas as toys, not understanding that clinging to a 1970s idea built on computers which are less powerful than toys today is limiting them.