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?
Managers and such get more facetime with their higher management which gets them access to better pay. VPs and the higher tier can see how much they get paid themselves so its easier to pay lower leadership more by comparison, while workers and experts are more removed and are limited to the managers budget