I don't think your calculation makes sense. You ignored the earnings multiple. Companies are valued at a multiple of yearly earnings. A reasonable multiple is 20, so divide 2 trillion by 20 first, then by 8 billion, and that's $12.50 per person per year. Their current revenues are already over $9 per person per year!
Now consider that in addition to search Google owns the single most widely used consumer operating system and web browser, the largest video site, a growing cloud business, the only alternative to Nvidia silicon for AI that's been deployed at scale, and other stuff like Waymo that has the potential to be enormous (it seems like a winner take all market to me, where the winner essentially owns all ground transportation, and Waymo is in the lead by far), plus still the largest AI research program in the world (even if it has had trouble turning that into products so far).