While I agree with your general sentiment, in fairness, Powell didn't say "revenue", he said "earnings", which is near equivalent to profits in financial reporting lingo.

But the AI companies do not have profits. Even Google/MS/Meta are probably subsidizing AI with the profits from their non-AI businesses.

I assume that in this context is basically about NVIDIA, and some other chip companies.

But NVidia's AI related profits are driven by the AI-related speculative spending in the uncertain hope of future profits by firms in the AI gold rush, they are just the leading seller of shovels.

Powell is so influential as the Fed Chair that he’s constrained in what he can even say. If he outright says there’s a tech bubble, that statement alone could cause the bubble to pop. I’m not convinced these are his actual views - he’s saying what needs to be said to protect the economy.