Work becomes even more performance art where you need to make the boss value you the most. All gameable metrics will be gamed.
To be fair, running a huge megacorp is really hard and there seems to be no easy answer to getting thousands of people to perform optimally, together, over the long term.
It's only hard when you're constantly trying to squeeze more money out and trying to cut wages and make people work multiple peoples' jobs.
I feel like helping a coworker should be factored into your performance. "force-multiplier", or however the industry calls it. but then, I've never worked at a toxic, hyper-competitive rank-and-yank..
This is how you get voting rings where there's an old guard on the team who help each other get good reviews, and a steady stream of sacrificial team members who are doomed to be in the bottom x% regardless of their competence. "Hire to fire" is another symptom of this blight.
These are rough, rough approximations of the human condition. The idea is that you can lossily compress 40 hours of work into 1 number, about a centimeter across on a computer screen. You WILL lose a lot of data.
That's why you have mentoring as a metric.