Average returns don't mean actual returns. On the surface this doesn't sound like it would be a huge issue. But it is. In addition, the benefit of a 401(k) tax deferral used to be estimated about 9%, but not anymore. And fees continue taking a steady told each year which erodes your compounding base. These factors, as well as liquidity issues and insufficient accumulation of funds in most plans are prompting people to save in other vehicles even if they continue to use a 401(k).