Probably the same reasons that the vast majority of software engineers don’t read anything about how to be good engineers, the majority of welders don’t read an

Probably the same reasons that the vast majority of software engineers don’t read anything about how to be good engineers, the majority of welders don’t read anything about welding, the majority of baristas don’t read anything about coffee making, and the majority of people working in fields with continuing education requirements hit the legal minimum on the nose. Plenty of people will learn only that which they perceive to be required and no more. People managers don’t seem to be an outlier here.