it would not surprise me to learn that in fact 80% of Oracle employees have turned over in five years (assuming the average employee is staying less than four years, which is consistent with what I have observed at similar big tech)

I once interviewed with Oracle Cloud (when it was going through its big-rewrite), and I was told the goal was to staff it with entirely new, not-Oracle people...the conclusion being that the first incarnation of Oracle Cloud failed partly due to staffing it internally