Is Social Security enough?

No. Given an extended life expectancy and a contracted employment period, a wage-earner must accumulate either after-tax assets in an amount sufficient to generate the required post-employment income stream or accumulate pre-tax assets or a pre-tax "promised" annual benefit in an amount sufficient to generate the required post-employment income stream. Social Security isn't enough.

Historically, for those who survive the employment period, the most characteristic support pattern is a reverse income transfer from children to parents. Today, it seems less common for parents to live with children. Some high net worth individuals live on investment income or by liquidating capital. But for others, the church and charities provided the safety net. Now, Social Security is a collectivized successor to the reverse transfer system - children support parents through the Social Security Federal Transfer Tax System rather than individually within the family.