Employee-supervisor skill inversion word/phrase request

Solution 1:

There are various phrases regarding this kind of managerial competence that may be useful:

"The Dilbert Principle": People are promoted to management because they lack competence in their technical role. In management they are "out of the way", thereby improving the workflow. https://en.wikipedia.org/wiki/Dilbert_principle

Under the Dilbert principle, employees who were never competent are promoted to management to limit the damage they can do.

"The Peter Principle": People are promoted based on good performance until they reach a role that is too demanding for them, where they underperform and thus are not promoted further. Thus everybody in the hierarchy inevitably finds themselves in a position where they are incompetent / underperforming. https://en.wikipedia.org/wiki/Peter_principle

People in a hierarchy tend to rise to "a level of respective incompetence": employees are promoted based on their success in previous jobs until they reach a level at which they are no longer competent, as skills in one job do not necessarily translate to another.

"Putt's Law" is similarly related: https://en.wikipedia.org/wiki/Putt%27s_Law_and_the_Successful_Technocrat

Putt's Law: "Technology is dominated by two types of people, those who understand what they do not manage and those who manage what they do not understand." Putt's Corollary: "Every technical hierarchy, in time, develops a competence inversion." with incompetence being "flushed out of the lower levels" of a technocratic hierarchy, ensuring that technically competent people remain directly in charge of the actual technology while those without technical competence move into management.

Unfortunately there does not seem to be a term for your very specific example of upper-level managers not being familiar with the details of what they manage due to having switched industries, but I think "Putt's Law" best encapsulates the aspect of management not having a technical familiarity or proficiency in what they are managing.