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?
“Leadership” is a nebulous identifier that enables corporation CEO’s to get huge, gigantic, colossal monetary bonuses for very little work actually accomplished. If a company ends up with good staff and good employees it somehow gets attributed to the CEO, even though they are the furthest removed from the process.