Because (during inference) the LLM is reset after every token. Every human thought changes the thinker, but inference has no consequences at all. From the LLM's "point of view", time doesn't exist. This is the same as being dead.
The "time" part is what I don't get. If you want to say that "resetting and reingesting all context fresh" somehow causes a problem, that I can see. If you want to say that the immutability of the weights is a problem, okay great I'm probably with you there too. "Time" seems irrelevant.