It's also a marker of the four-decade-long debate over defined-benefit (aka traditional corporate pensions) vs. defined-contribution plans that are more employee-directed.
The generations of workers who have come of age in the post-World War II period mostly haven't had the option of choosing a pension. That said, the 401(k) program has grown, evolved and provided no shortage of tax and flexibility advantages over time. Forty years on, the reviews are mostly positive.