No it's entirely plausible that hiring then was the right decision and firing now is the right decision. There's no universal law that says you must hire people for eternity.
Why do you feel the urge to make excuses for managerial incompetence.
Like when you are a worker, they must be scruitinised to make sure they arent lazy or incompetent, but the day you get promoted to executive you gain godlike immunity from criticism
In the past 40 years several FTSE 250 companies have collapsed, gone bancrupt or suffered some other disaster.
I can't name any example where shareholders replaced upper management before it was too late. Can you?