I wonder if it has more to do with the fact that the more inputs are available, the more complicated and prone to error something is. Also, ChatGPT doesn't "get tired" or at least not in the human meaning, I guess it could exhaust the memory of whatever its running on would be the closest analogy if my understanding is correct...
Re:complexity, this is true of all things, and computer/programming stuff is no different. The more complex it is or the larger the dataset, the greater potential for noise vs signal