Psychology
People stick with what they've already got, even when switching is free
In 1988, Samuelson and Zeckhauser found that when people are given a default option, they disproportionately keep it rather than choosing a genuinely better alternative — true for retirement plans, health insurance, and even hypothetical inheritance windfalls in lab experiments. The bias survives even when switching costs nothing, which is why the exact wording of a default option can shape outcomes at a national scale.