What is the best contribution one can make to better a society?

I was once asked by a prominent industrialist - What is the best contribution one can make to better a society? Make billions, spend billions, or give away billions?

This was my answer:

The best way is to do both: To make billions, spend a little less, save the rest and give it away! Twenty percent of your earnings should be earmarked for charity. However, charity should be self-sustainable. That is, it should create more wealth rather than perpetuating the cycle of poverty and dependence. In this sense, the best form of charity would be providing quality education for children and more importantly, building a good character in them. 

In the 11th chapter of the Bhagawad Gita, Lord Krishna said, "Win the war with enemies and enjoy a prosperous empire." How can a businessman be altruistic and yet follow this piece of advice? Is there a way to resolve this riddle? Krishna's advice was not for a recluse, but addressed to a prince. The Gita should not be dismissed as a text for people who are not in the world. In fact, the Gita is of no use for people who are retiring from the world.

The entire Bhagavad Gita is focused on the prince who had to shoulder a huge responsibility, encounter complex situations and solve complicated human relations to make the country productive. Any big business has to perform all these functions. The promoters and leaders have to manage human resources; resolve conflicts. One cannot be emotional and say, "I don't want to compete with anybody. The world of business is always a struggle, a fight. Your weapons are speculation, bidding, negotiation, branding, marketing, pricing, innovation etc. These are the weapons for you to fight the business wars and you should fight it to your complete satisfaction. If it does not turn out to be viable, naturally you lose your fight. (Non-viability, heavy competition, lack of HR, labour problems) 

You can't do business with a charitable mindset. Charity and business should be kept separate. However when it comes to enjoying the fruits of your business, you should have a charitable mind. You must keep aside a portion for charity.