Yea, every progeammer should write at least a cpu emulator in their language of choice, its such a undervalued exercise that will teach you so much about how stuff really works.
You can go to the next step. I studied computer engineering not computer science in college. We designed our own CPU and then implemented it in an FPGA.
You can go further and design it out of discrete logic gates. Then write it in Verilog. Compare the differences and which made you think more about optimizations.
Older people are always going to complain about younger people not learning something that they did. When I graduated in 1997 and started working I remember some topics that were not taught but the older engineers were shocked I didn't know it from college.
We keep creating new knowledge. It is impossible to fit everything into a 4 year curriculum without deemphasizing some other topic.
I learned Motorola 68000 assembly language in college. I talked to a recent computer science graduate and he had never seen assembly before. I also showed him how I write static HTML in vi the same way I did in 1994 for my simple web site and he laughed. He showed me the back end to their web site and how it interacts with all their databases to generate all the HTML dynamically.
The universe underneath the pie is mostly made up of invariant laws that must be followed.
The OS, libraries, web browser, runtime, and JavaScript framework underneath your website are absolutely riddled with bugs, and knowing how to identify and fix them makes you a better engineer. Many junior developers get hung up on the assumption that the function they're calling is perfect, and are incapable of investigating whether that's the truth.
This is true of many of the shoulders-of-giants we're standing on, including the stack beneath python, rust, whatever...
When I was a kid I "wrote" (mostly copied from a programming magazine) a 4-bit CPU emulator on my TI-99/4a. Simple as it was, it was the light bulb coming on for me about how CPUs actually worked. I could then understand the assembly language books that had been impenetrable to me before. In college when I first started using "C", pointers made intuitive sense. It's a very valuable exercise.
