My brother works for a company like that. Lucky for him, he has a wife who is willing to be a “trailing spouse.” Those workers who are not so lucky don’t advance.
Also, breadth and depth within a subject, and the accessibility thereof, can differ for different subjects. The accessibility can be noted by comparing the volume and sequencing of prerequisite courses needed to get to where one can explore the breadth of the subject or get deep enough to understand the subject’s frontiers of knowledge.