[faidit]

That future promise doesn't do much good if the planet is dead by the time these guys get around to donating, thanks to the ecological catastrophe caused by their supposedly well-intentioned greed. Also, EA proponents tend to ignore society's opportunity cost here - that money could have been taxed and put to good uses by the public in the meantime. Whatever the inefficiencies of the public sector, at least we can do something to fix it now instead of trusting the promises of billionaires that they will start giving back one day.