As a hobbyist coder, I wonder how much more new code, fundamentally, there needs to be? New devices need new firmware, new cars etc, but how much of that is bes

As a hobbyist coder, I wonder how much more new code, fundamentally, there needs to be? New devices need new firmware, new cars etc, but how much of that is bespoke? Sure, a new movie or a book is new entertainment, but I've already seen that movie and read that book, they just had different jackets. What do these "engineers" actually do that is novel and how much of the pizza is the novel slice is?