Software is also part of the world, just a very different part.
But AI is not replacing processes that rely on software with something that no longer relies on software. What AI is doing is it lets you replace even more processes that were not yet able to be handled by a computer with one that a computer can do, and thus it just helps Software eat even more of the world. Decision making and judgement tasks were not able to be successfully moved to computers prior to the recent advancements in AI, now some of those can be.