The fee introduction didn't lead to the resignation of the Unity CEO. He was brought in to do the layoffs, make necessary buisness decisions, and leave with a golden parachute for being the scapegoat.
Source: Was Unity dev for 3 years, including during this fiasco
According to Wikipedia, John Riccitiello was CEO from 2014 to 2023. So I think your facts are off, unless Unity was planning layoffs and fee changes nine years in advance.
Instead, note that Unity went public in 2020. I expect Riccitiello was pushed by the board to improve profitability, then left with a golden parachute for being the scapegoat.