There are a million political forces they would have to deal with to "fix the current planet," and they already do give to charity. Beyond that, you might ask,

There are a million political forces they would have to deal with to "fix the current planet," and they already do give to charity. Beyond that, you might ask, "Why do these people do anything because they are so vastly wealthy?" It is a passion project that inspires and motivates them, and the people that work for them. It is their money to spend.