I wrote this in the context of the article, where a Google developer with 33% more productivity would already have progressed to the next role level. At least, that is what I would assume for large companies.
Promotion is not centered primarily around productivity, at least not beyond SWE2 or whatever the second engineering level is in a given company. Ability to lead/influence at a scope larger than self is largely disjoint from individual productivity in coding.
