Currently scaling limitations where gain outweighs the cost efficiency. True long term reasoning. Hallucinations and pattern matched reasoning over structural reasoning. Reasoning for novel tasks. Hitting a data wall so lack of training data. Stale knowledge. Biased knowledge. Oh and let's not forget about all the security related issues nobody likes to talk about.

So just to be clear when you mention "AI" you're mostly talking about LLMs right? Since most of these don't apply to expert systems.