> Studying past highly-successful systems and understanding why they made the choices they did is not just useful but essential.

Studying currently used and developed systems for people who will be designing future ones and enter job market in near future is more essential. Databases designed today are mainly distributed and knowledge of design choices made by Postgres doesn't help there, same as design choices made by whatever existed before Postgresql.

> Most of what you would learn from implementing a map or regex parser is way above the hardware

Ok, I agree with that. Although I am testing now hash implementation written using SIMD instructions. My main point here was however that while you see map and regex parser as some building block that people should know how to build, I am saying that the building blocks today
are things built on top of them. This moves whole thing one layer above, and makes the question of "how does map work internally" into the same territory as "how is nand gate built internally" for C developers: totally irrelevant. Programming courses were focused on teaching how to write hashmaps and sorting algorighms for decades, but here is the news: we already have them, start teaching how to use them to build higher-level things.

> Go ahead, try to name a language that better represents hardware.

Assembler. LLVM IR. C or C++ with custom extensions. Whole families of languages for graphic cards.

> representing the hardware is not the point anyway

Oh, that's what I think too. That's why I see C as obsolete: if you don't need it to represent hardware (which it doesn't) and rely on compiler doing optimisations for you, you can as well use more convenient language (like Rust. Or Java), which will provide the same end result with a lot of added value. Like actually making use of the hardware easier for example.

> Apparently some people think that anything below the web browser is hardware.

The implementation details of anything below the web browser is indeed mainly dictated by hardware. How the web browsers are designed too: all changed significantly to utilize parallelism and accelerated graphics because that's how hardware works today.

> you'd know that making something teaches lessons in ways that abstract thought can not.

Definitely. But it helps a lot if that "something" will be relevant to your future work.
C largely isn't, outside of relatively shrinking domains.

> You wouldn't. The implementors would.

Yes. But implementors would not look into "how to write C code", but into "how specific hardware works" to make things efficient. People who write compilers today look into either hardware specs, or models exposed by code generators. That's another niche where C is not the king anymore.

> Your attitude is effectively "it's magic" even if you don't use the word.

True. I consider certain amount of layers below what I work on as "magic" in the sense that it makes no sense to me to know how it works in details, only to have some mental model.
It is useful for me to know that CPU has registers and cores, it is not useful to know how to produce it. I also know that whatever people work on today, will be covered by more layers tomorrow. Of course someone will need to know to build a CPU or how to write a regex parser, but we come to time when we spend 99% of time just using them and the need to building or redesigning one appears maybe once a decade. A lot of things the people teach when they teach C is very useful for people who will be using C professionally, and largely useless for 99% of those who will use something else because the world moved on higher or lower for the things that C was used before.