Why Do Rich People Hoard Their Money?

SETI only needs $5 million - otherwise it will shut down for lack of funding. With all the multi-millionaires and billionaires out there, none of them were willing to step up and fund this? I don't understand why rich people seem to hoard and protect their fortunes in these "modern" days. There are people so rich, they will never ever be able to spend it in their life times. Yet still, they hoard.

Budget Cuts Shutdown SETI's Alien-Seeking Telescopes : The Two-Way : NPR