Unless the world is in for a nasty spill, the richest people likely will become even richer over the generations. Other than buying out or bribing African dictators, what else might the truly rich do with their money?
1. Build artificial islands, create jobs there, take in immigrants, and experiment.
2. Change their names to "Nemo," and hire mercenaries to intervene when Darfur-like situations get out of control.
3. Finance excellent movies just for the heck of it.
4. Send out self-replicating, solar powered von Neumann probes to explore the galaxy and look for life, or perhaps seed life (did anyone get a tax deduction for doing Earth?).
5. Create galactic spectacles which are obviously the work of intelligent beings, to advertise our presence to other civilizations, or future civilizations, throughout the galaxy.