Surely that can't be right? The US + Canada together have a population of under 380M. Even your low-end ARPU number of $1200 per year would imply North American revenue above $450B, far higher than Google's entire 2023 annual revenue of $300B [0].
(Even correcting for market share isn't enough, as Google Search has over 90% penetration in the US [1].)
Definition of user is doing a lot of lifting here, if I remember it was like signed in, 1da, 2+ products. Scope and scale at google made things really different than other places.
They defined users from a business sense as something we wanted to achieve within the product ecosystem -- not just randos using the product occasionally
