Of the tech economy, perhaps. Or perhaps that's what you meant by "our", this being a tech site.

A huge amount of the workforce is engaged in work that doesn't change much at all. Construction workers, skilled labor like service plumbing or mechanical maintenance, engineering, retail work, etc. It's fairly optimized and if it changes, it changes in reaction to something or because new technology opened new opportunities. Really, it seems like mobile and web applications are the most stuck into this loop of having to add something new. An emacs users who used it 25 years ago could still use it today.