[Google's chief scientist leaving](https://www.cnbc.com/2026/08/05/google-chief-scientist-jeff-dean-leaving-company-after-27-years.html) after 27 years isn't a headline about AI strategy—it's a headline about retention. Dean didn't leave because the org chart improved; he left because the incentives or culture shifted enough that staying stopped making sense. That's the tell. Reshuffles look decisive on earnings calls. Talent walks out the door when the mission feels compromised.