James Surowiecki notes that a majority of seniors voted Republican in the recent election. He finds some irony, but is not surprised, that seniors' attitude prompted by Obamacare was "I've got mine -- good luck getting yours." It's linked to today's economy. He cites Benjamin Friedman's The Moral Consequences of Economic Growth. People are less likely to be generous when times are bad. Yes, Social Security was enacted in bad times, but things were so bad then that social solidarity took over.
There is always more than one story. People not living in welfare states tend to be more generous. Here is a cross-country comparison of charitable giving. Daniel Hannan cites US-UK comparisons of giving that are even more stark.
I hope that the evolution of the US welfare state has not pushed us to the point where we are less generous with others.