I've heard this as well. Probably true in some form. Yes, there are some rather good managers in PHX that are reasonable and fair and have a high level of personal integrity that I would hate to see go. Sadly, the management culture in PHX is not conducive to retaining managers of this type. On the other hand, there are those that are insensitive, conniving, and willfully negligent to the point that their departure would be cause for celebration.
Can't say they didn't know the risks going in, managers generally enjoy zero job protections even under the best of circumstances.