Beyond a few million a year, the rest of the comp is really providing something that's more difficult to purchase with money: power. So, while there's a diminishing return on the benefits of additional money in a person's life, a certain subset of people have an insatiable desire for more power. It's problematic in what's supposed to be a democratic society with a fairly flat amount of power distributed among citizen…
Fundamentally, no one is qualified to make decisions for anyone else in the first place, and the way we ensure the fitness of our civilization is to disaggregate and decentralize power.