I don't find the advertising argument very convincing.
If you were the advertiser, be honest, how much would you pay for Google Ads? Considering how effective it is, I doubt it would be very much.
And think, Google have a huge amount of R&D, some of which is never commercialised, all of which requires top professionals in their field. It doesn't seem to add up. How can Google really be the biggest technology company right now, and probably the biggest ever, just from the advertising revenue that 80% or 90% or users never engage with?
Are you kidding. That's one of the funniest things I have ever read. You should consider a career in standup.
https://www.statista.com/statistics/266249/advertising-revenue-of-google/