In practice, you see a lot of these self-professed Judeo-Christian moralizers engage in irresponsible individualist behavior so I don't think paying lip service to religious morality is really effective here either. The overriding factor is still the structure of incentives rather than adherence to a specific moral code.
American culture has transformed over the centuries, but the most recent dominant form is hyperindividualist. Ayn Rand over Jesus Christ.
Just look at our most recent leaders -- a couple of highly corrupt guys with no serious religious conviction.
We have no government armed with power capable of contending with human passions unbridled by morality and religion. Avarice, ambition, revenge or gallantry would break the strongest cords of our Constitution as a whale goes through a net. Our Constitution is designed only for a moral and religious people. It is wholly inadequate for any other. -- John Adams
Our culture is predicated on not elevating individualism and freedom above responsibility. They go hand-in-hand. When morality becomes relative, and "whatever feels good" is the standard of acceptable behavior, you see the sort of social decay that is happening all around us.