Stability is for sure a very seducing trait. Also I can totally understand the fatigue of the chase for the next almost already obsolete new stuff.

>There's no reason we can't be writing code that lasts 100 years.

There are many reason this is most likely not going to happen. Code despite best effort to achieve separation of concern (in the best case) is a highly contextual piece of work. Even with a simple program with no external library, there is a full compiler/interpreter ecosystem that forms a huge dependency. And hardware platforms they abstract from are also moving target. Change is the only constant, as we say.

>Imagine having this attitude with math: "LOL loser you still use polynomials!? Weren't those invented like thousands of years ago?

Well, that might surprise you, but no, they weren't. At least, they were not dealt with as they are thought and understood today in their contemporary most common presentation. When Babylonians (c. 2000 BCE) solved quadratic equation, they didn't have anything near Descartes algebraic notation connected to geometry, and there is a long series evolution in between, and still to this days.

Mathematicians actually do make a lot of fancy innovative things all the time. Some fundamentals stay stable over millennia, yes. But also some problem stay unsolved for millennia until some outrageous move is done out of the standard.