Hey OP, you are being overly pessimistic. The way I see it, people often do believe in helping others and altruism and the like, but the thing is not that they think 'what's in it for me?', but rather 'what can I really achieve?'. You are right, after thousands of years of civilisation, the undercurrents of hatred, greed and all kinds of other terrible forces simmer just under the surface of many of society's pretensions. But there are others just like you who are worried about society and are genuine about love, etc.
The trick is to move past the pessimism and activate others' altruistism. For that you need a great deal of self confidence and motivation. I know that my thinking is borderline hippy, but meh. What's so bad about some of the hippy ideology anyway?