Pretty much every company I’ve been in or know of values a vertical trajectory instead of a horizontal one for its employees i.e becoming a manager nearly always means a faster salary progression than becoming an expert in one or multiple fields.
Why is expertise valued less?
It’s a lot easier, more reliable to promote your son to VP than Senior [blank] Engineer. Also, for some weird reason we could never have predicted if we wanted to create a more efficient and equitable system, the people who decide salary decided they should have the biggest salary by a lot.