Almost all of the work in making a new operating system or a gameboy emulator or something is in characterizing the problem space and defining the solution. How do you know what such and such instruction does? What is the ideal way to handle this memory structure here? You know, knowledge you gain from spending time tracking down a specific bug or optimizing a subroutine.
When I create something, it's an exploratory process. I don't just guess what I am going to do based on my previous step and hope it comes out good on the first try. Let's say I decide to make a car with 5 wheels. I would go through several chassis designs, different engine configurations until I eventually had something that works well. Maybe some are too weak, some too expensive, some are too complicated. Maybe some prototypes get to the physical testing stage while others don't. Finally, I publish this design for other people to work on.
If you ask the LLM to work on a novel concept it hasn't been trained on, it will usually spit out some nonsense that either doesn't work or works poorly, or it will refuse to provide a specific enough solution. If it has been trained on previous work, it will spit out something that looks similar to the solved problem in its training set.
These AI systems don't undergo the process of trial and error that suggests it is creating something novel. Its process of creation is not reactive with the environment. It is just cribbing off of extant solutions it's been trained on.