It's part of the contract for most standard corporations (that aren't B Corps) - the management has a duty to do what's best for the company, which usually comes out to "have a good reason behind doing something". If Amazon comes out tomorrow and says they're throwing in the towel and giving away their money to the Seattle poor because that will have a more positive impact, the lawsuits will be immediate and fairly one-sided. It would be a fairly easy case to argue that Amazon would be failing in their duty to shareholders by spending their money on something with no hope of an ROI.