Google has so many channels for ad delivery. ChatGPT is only competing against Google Search, which is arguably the biggest. But dont forget, Google has YouTube, Google Maps, Google Play, Google TV and this is before you start to consider Google's Ad Network (the thing where publishers embed something to get ads from Google network).

So nope, ChatGPT is not in even in the same league as Google. You could argue Meta has similar reach (facebook.com, instagram) but that's just two.