Well, one reason is that without metrics, prejudice and bias is much more likely to win the day. "I just don't feel like they're doing a good job" is affected by all kinds of things unrelated to actual performance. At least having some metrics require you to think about whether that feeling is backed up by reality.

the theory is that high productivity people will not want to work there, as everyone else benefits from their excellence. If companies that retain these high productivity people perform better than companies that don't, evolutionary pressure will force these egalitarian companies out.

I think this theory may be true in some fields like hedge funds or heavy sales performance based businesses.

In software, I am not sure high productivity people care about this issue, as long as their compensation is high enough.

> high productivity people care about this issue, as long as their compensation is high enough.

That circles back to the original problem of how do you identify the high productivity people to give them high compensation. It works when the person spending the money is close enough to evaluate employee performance. But when it's some middle manager spending Zuckerburg's money you run into the agent/principle problem. The managers will do what's best for them (raises for everyone!) and not the enterprise.

I think high productivity people by definition cause everyone* else to benefit from their excellence.

So high productivity people who don't want everyone else to benefit are a bit of an oxymoron.

(* or at least most others)

LeBron James wants his whole team to succeed, but he still expects to be paid the most.

If you can afford LeBron, great!

If you can find a dev who can do for your company what LeBron can do for the Cavs/Heat/Lakers, great!

The reality is that you should be shooting for Shane Battier.

Being productive and not blocked is all some people want. Some might want to do less. And some might want to feel like they are the mvp. Michael Jordan didn't mail it in because Scotty was sitting at home.