This right here. You do need grading. Is it imperfect? Of course. Yet, it also serves a selection criteria. Who gets to enter certain fields or get certain positions. You need something quantifiable so it isn't just who knows who or who has money.
Performance metrics are trickier because they often come with perverse incentives that have very tangible real world consequences.
This is an absolutely true story. I was working for a networking company way back and they outsourced part of the stack development. It literally came back with repeated blocks of code that should have been in a loop. I queried and they literally paid the contractor by line of code. Or you have the example in the article about doctors prescribing tests to make their numbers look better. Or even school/medical care classifying people with 'greater' disabilities or ailments so they get more funding...
In this respect, I do think we need a greater respect for just doing an honest days work. We at times have to accept it's too difficult to properly and perfectly metric something and just rely on people doing their job and being monitored by managers and coworkers and 'customers' for doing their job. Maybe you are an amazing developer, but maybe you're not paid 10x a regular developer. Maybe you're an amazing police officer, but you're paid in the same pay band as just a regular police officer. That's just part of the job. If you try and apply metrics to it like number of tickets or arrests made, that can have some bad legal consequences for citizens. Same with teachers.
This idea of always rewarding the 'best' according to some 'metrics' to make it seem objective is perhaps not the best solution.
I emphasize the term 'seem objective' because it's often not correct or is used to force something against other opinions because of metrics.
I'll give another related topic on metrics. I'm in Toronto, Canada and we've had a massive transit investment in the past few years. Of course deciding where or what kind of transit to build is complicated. What bothered me is the number of 'reports' that were provided and politicians basically using these 'reports' to push a political view point under the guise of it being objective and 'science' based.
The one that hit me was debating LRT versus subways. I actually went through these reports and basically they revolve around what you choose to weight.
If the report chose to give a high weight to having more stations close to people... guess what LRT wins because there are typically more stops.
If the report chose to give a high weight to time to destination... guess what subway wins as it's removed from traffic and typically fewer stops.
You basically didn't even need the report. All you needed was what the 'academic' doing the report chose to weight things. If you know their 'values', you know their 'weights', and you know the result of the report.
Instead of having a values discussion, which is actually what was at play (more people close to a stop VS time to destination), both sides just bashed pointless reports at each other claiming to be 'objective'.