Perhaps you should ask yourself why any successful business person would EVER sacrifice their time and resources to help others. They do it every day, so there must be a reason.
It's because some things in life are worth more than money. And I can assure you that helping others along their journeys by sharing your own successes and failures is one of those things. And you want to know why that is? It's because helping others gives you something back that money in itself cannot. And that's joy. It's a powerful feeling and anybody who's truly experienced it wants more of it.
And any super-successful person isn't naive enough to believe that he achieved his success all on his own. He knows deep inside that he had some help from other people along the way in a variety of ways. So it's only natural to express thanks by turning the table and helping others who haven't achieved a similar level of success yet.