While chat LLMs can be dumb with very simple requests, I think that for many users they don't work because most people cannot explain things well. Not because they are dumb too (this happens though) but because most assume that everything they know is common knowledge. While with LLMs (and with people for that matter), if you want to be understood, you must assume that the other side doesn't know anything.

Hence the importance of prompt engineering. But it's not really engineering. It's just how you should talk so that others understand you.