AI is still fueled by hope.
The actually applications of it (they do exist and they are valuable) pale in comparison and value to what it's valuation is based on, it's future promise.
When the people who say things like "AI is going to replace all accountants!" stop speaking the the future tense, it's value will be justified. For now, it's OpenAI spending billions developing a product they hope will make trillions and Nvidia is happy to sit in the background selling billions of dollars in compute.