The original proposition was that essentially an oligarchy is more efficient than our current system: billionaires will waste less money than the government on

The original proposition was that essentially an oligarchy is more efficient than our current system: billionaires will waste less money than the government on inefficiencies. In that light I don’t mean consequences as punishment but rather incentive. Why should a billionaire spend money on socially useful project vs a self-serving or a socially harmful one?