your goal as a person hiring (or firing) is to assess the candidate's ability to consistently make efficient decisions given complex scenarios with many rotating pieces. can this person handle their responsibilities and grow with them, or will they be difficult.
some of the most technical and capable people also have terrible interpersonal skills and a fickle work ethic, which means they follow their interests and not yours. do you want to herd cats or work as a team? teams need leaders, leaders need respect and to be followed. a working environment is a benevolent dictatorship not a democracy. if flat structures worked they would be applied broadly across fortune 500 companies, are you a wheel inventor?
it takes about 6 months to train almost anyone to do almost anything in the modern digital/information world. it takes a lifetime to be agreeable, polite, conscientious, patient, dedicated, unbiased. you'd learn a lot more about someone watching them interact with strangers and friends for 5 minutes than from hours in interviews (which ostensibly they have crammed for and are hiding as much of their weaknesses as possible). i assume this is why so many companies want private information on their employees, social media, public profiles. hiring at the moment works as a great filter, there is no best candidate for any job, a better strategy would be to filter out personality traits which would clash with company direction and assume some level of skill training will be required. pretty sure this transition is already happening.
the real stickler will come when hiring agencies realise basic fitness and hand eye coordination tests are better predictors than technical ability, then you enter into some genetic discrimination areas which will only accelerate the relevant bio-technologies, a fissile cavitation.