its an information and principal agent problem.

We don't know how to measure worker productivity -> its hard to even say what a good hire is.

We don't have good standardisation around whatever measurements we do take -> hard to say anything about hiring at all.

People are more interested in their own prestige than hiring the best option for the company -> too many candidates get hired in the wrong places.

many of these problems do seem solvable given risk taking and statistics. However, culturally hiring managers aren't inclined to do either.