Late Stage Capitalism

At that point of wealth you aren't thinking about spending money as an individual, or even an individual family (even including hangers on and staff). You are essentially a representative of a power that parallels governments, with worldwide reach, and will think along those lines. You want to implement worldwide policies, dictate the tides of capitalism, play with your own regime change politics, break the barriers of old age, gene manipulation, and get the process started on astro-mining and colonizing Mars.