Sometimes doing nothing is the best strategy but it's hard to get promoted that way.
IT culture in general and Google especially puts too much pressure on engineers to re-invent the wheel to get better visibility and promotions.
(Plenty do out of love for the product/customers/etc, but man it's soul crushing to not be recognized for it)
My understanding is that not everybody there knows where the corporate ladders are. If you don't (yet) know the terms of promotion at the GOOG, you'll be happy to knock out bugs and tweaks day in and day out. You're a Googler!
For example everyone says value "work life balance is balanced here and encouraged". But irrespective of whether they actually do it or not - if the two people output around the same ballpark but one is visible as more serious/responsible and seems more invested usually by virtue of more hours at work that becomes more "visible" than the "casual" 7-8 hr person with the same output.