But isn't it more likely that the AI will take a copy of the library it cares about, host it on its own datacenter, and then invest a few subjective months/years rewriting it, benchmarking it, documenting it, etc. until it is a gem of software perfection, and then a few objective seconds/minutes later, sends out an email notifying the relevant humans that their version is hopelessly obsolete and pathetic, and they can go work on something else now?

Can you think of many programmers who would want to spend a few months on that while living in a solitary confinement chamber? You wouldn't have the objective time to exchange information with other people.