Return to academia [in administration] from industry
In my limited experience, high-level administrator posts filled by current-or-former academics fall under one of the following categories:


Ex-officio with being a Full Professor somewhere (with perhaps some rotation among Professors)
Carried out by regular Full Professors on temporary leave from their academic duties, or in parallel with a much-reduced regular academic workload.
Carried out by Professors Emeritus, or people who academically-retire early from their position as Full Professor to do only managerial work
Populated only by people who have a special long-standing relation with the academic institution (and aren't Full Professors).


I have encountered a few exceptions to the above, but those were extremely rare.