I don't think this is the case at all. There is nothing in the spirit of hackerdom where "I got mine" is the standard mentality. In fact it flies in the face of OSS development where people are interested in doing something because they thought it was cool and wanted to share it. Or they found a solution to a problem everyone is having and felt that the best thing to do with it is to give it away.
Saying that someone has gained something by doing charity is a very Randian point of view. Maybe PopCap thought it make them look good. Maybe they thought it would make them feel good on the inside. Or maybe they felt like doing because some kid asked and they thought, "oh, what the hell".
Further, I agree with the other commenter.. I don't really see the entrepreneurial spirit is ripe with 'out for yourself' mentality. Sure.. people are hustling, but most of the entrepreneurs I know are doing it by focusing on creating real value for people. I'm pretty thrilled with the brand of hustle I've been seeing in the last few years in this respect.