> I'm pretty sure you didn't go through Στοιχεία (The Elements) in its original version
This is like saying "you haven't read the source code of the first version of Linux". The only reason to do that would be for historical interest. There is still something timeless about it, and I absolutely did learn Euclid's postulates which he laid down in those books, all 5 of which are still foundational to most geometry calculations in the world today, and 4 of which are foundational to even non-Euclidean geometry. The Elements is a perfect example of math that has remained relevant and useful for thousands of years.
So that's it. Just because new languages and framework are rising and fading away, it doesn't mean there is nothing kept all along the way. It just that specific implementation is not the thing that people deem the most important to preserve over time.