The US has a public pension scheme called "social security," which guarantees at least a minimum level of income in retirement to all citizens (although, not enough to live on IMO).

This is intended to be supplemented with private investments via 401k & IRAs, which are actually relatively new programs (created in the late-1970s, but nobody even talked much about them until the 90s).

So while most millennials understand they need to be saving privately in these vehicles (r/personalfinance has 15 million members), there's a huge forgotten generation in the middle who slipped through the cracks between the transition from industrial-era corporate pensions to personal saving.

These are the folks who will unfortunately bear the brunt of the retirement crisis, having to get by only on Social security.