If you put yourself in the shoes of an L3 or L4, you know this is not exactly true. Who your manager is and what their priorities are, and how they view the promo process can greatly affect your ability to get a promo. I mean, before you can apply you need to get "strongly exceeds expectations" for two consecutive halves. If you do great work that you think benefits Google, but your manager doesn't think you've sufficiently demonstrated things on the rubric (e.g. "google-quality delivery" or "autonomy") you won't get a promo. Managers also have their own agenda and list of things they need to deliver, so you end up having to work on things they want you to work on, even if they don't help you tick the boxes in the rubric. If you're lucky and get a good manager who helps you play the game, these things aren't problems. If you're well-informed, you know how to bail when you encounter such folks. If you get unlucky or don't wise up to how it works, you can be set back many years in career progress.