"I mean, "AI Mode" is the default result when you Google something"

No, it's not. AI mode is something you have to select (in the search window). There is an AI overview provided with your basic search results.

I agree with their assessment that '"AI mode" is the default' - https://ibb.co/Pz9LqKRb.

That's what I get, in the UK, logged out of Google, from a search in Firefox omnibar using "Google" as provider.

I'm aware that they have other things that can be described as AI modes.