[hirundo]

Google's search engine market share does not appear to be flagging as ads have become more intrusive:

https://gs.statcounter.com/search-engine-market-share

Given that, from a shareholder point of view they may be committing mismanagement if they don't monetize it even more -- at least until their market share at least reacts. Until they titrate enough ads into the solution for something to precipitate, they won't know if it's saturated yet.