If we continue the programming language metaphor: the same reason that nobody want to change the Cobol program on the old mainframe but is ready to rewrite more recent projects.

Because the constitution is nothing compared to the intent to follow it.

if fictional explorations of this idea are worth anything, le Guin's Dispossessed are a people whose determination to abide by a set of principles led them to write their constitution not just on paper but directly into the human language faculty

This is a good question that motivated a feature-length article published in The Economist this summer (which I've also referenced elsewhere in this comment section) [1].

The article argues that newer versions of constitutions often overly lengthy due to attempting to include too many laws within the constitution, which can cause problems. The article argues: "Overly long constitutions often create conflicts between articles that can only be resolved with further tampering. And “if everything is highest law, then nothing is highest law anymore,” points out Dr Versteeg. Omnibus amendments require voters to balance the merits and drawbacks of many changes at once, making it harder to generate consensus."

In brief, the article's view is that the inclusion of too many laws in more recently-written constitutions leads to greater incentives for constitutional rewrites as times and political views change, which is why the article takes a viewpoint in favour of shorter constitutions that guarantee fundamental rights, and are thus more difficult to rewrite.

[1] (Paywalled, though I've included a summary above): https://www.economist.com/international/2022/08/25/dictators...

Sounds like the constitutional version of popular JavaScript frameworks which quickly outgrow their intended scope and that nobody is ever fully satisfied with

That's a feature, not a bug.