Why would Google hire "poor performers" in the first place?
Google, in part, built credibility with its talent because it's hiring process selected for exceptional talent and Googlers levereaged this into basically a passport to work anywhere. Google is shooting itself in the foot by framing it this way in the sense that it destroys the illusion that they have better hiring practices has the cost of not attracting the exceptional candidates they once could.
Because it's an excuse to fire people, what else?
Also the company is producing bad products and nothing innovative at all. They just try to copy and fail, look at Stadia and others.
Without count Angular and everything around it.
The biggest problem with these stack rankings is that the variation isn't evenly distributed. Across the entirety of Google engineering half are below average, but they might all be in single division/group/team and you may be destroying extremely productive teams by forcing them to cut bottom performers.
Google, in part, built credibility with its talent because it's hiring process selected for exceptional talent and Googlers levereaged this into basically a passport to work anywhere. Google is shooting itself in the foot by framing it this way in the sense that it destroys the illusion that they have better hiring practices has the cost of not attracting the exceptional candidates they once could.