Assuming 2 years paid leave only works if your workers are non-essential and additionally more-or-less interchangeable. What happens if a person is hired for a

Assuming 2 years paid leave only works if your workers are non-essential and additionally more-or-less interchangeable. What happens if a person is hired for an essential role, then leaves for 2 years expecting their job back? Imagine like, a CFO or specialist mechanic takes 2 years paid leave. What do you do? You hire a new CFO/mechanic. You can't function well without one, certainly not for 2 years. Then when the paid-leaver returns, what do you do? Fire the person you hired to fill the gap? Have 2 CFOs or redundant mechanics on staff?