I work at Google and the who promotion culture is very toxic. People are incentivized to "Launch" things just in time to get promo and only to abandon it or switch teams in search of the next promo. It also gets hypercompetitive and harms teamwork sometimes. The promotions are usually B.S. anyway, they add stress and usually remove a good functioning engineer from doing good work into more "non technical leadership" work.
The Truth is, people really want promos for the extra money and more stock. I say, just give them the extra money and stock privately, and only promote people when there's a job to be filled for that position.