This is not just a good thing for Gravity's employees, it is also an enormously thought-provoking action at a time when such actions are rare.
Even imagining that high tech is a true meritocracy, which is a fairly dubious imagining, American companies are still floating in the sea of American business. And America has been heading towards historic levels of income inequality, higher than the levels that preceded the great depression. We tend not to learn our lessons until we shoot ourselves in the foot or higher. This CEO is demonstrating the obvious -- once you are making a ton of money, you can begin to share it with the people who have helped, are helping, and will continue to help you make even more, and this can have a positive impact not just on the people you are sharing with, but on YOURSELF as well, and on your society.
A positive impact on yourself, because you will be appreciated and honored for doing a very decent thing.
And, if your society were to pick up on your lesson, all sorts of good things could happen: it would be less likely that your children will get an infectious disease, because other children would be healthier; you would be less likely to have to pay for more prisons, because people are less likely to turn to crime when they are able to participate in a flourishing economy; you would not need to invest quite so much in alarm systems for your mansions. You might find the public schools improving because there would be fewer people going to private schools. You might even need to invest less in a military because with less income inequality, the politicians' focus might change from protecting our billionaire class' stolen overseas assets to protecting our country while aiding the poor in our own and other countries.