For instance, the size of their DC plan contributed to the interest of employers in using a state-run plan rather than retaining their own.

The post says, "Plan sponsors with larger DC plans (over $50 million in assets) were more inclined than smaller DC plan sponsors (under $10 million in assets) to say they would replace their existing DC plan with the state-run plan (31 percent versus 22 percent)."

One reason employers are so interested in bailing on a DC plan in favor of a state-run plan is liability.

The potential for plan lawsuits is a major driver in their interest—but the lack of a number of important features in government plans that are incorporated into employer-sponsored plans could have a major negative effect on employees' ability to save adequately.

For instance, the blog post points out that while many state-run plans are designed as IRAs, thus limiting investors under 50 from contributing more than $5,500 per year, DC plans have an upper limit of as much as $18,000.

Workers, of course, want higher limits than government plans allow, with 86 percent of workers saying it's important to be able to set aside more than $5,000 a year.

If an under-50 employee making $75,000 a year is saving 10 percent in a DC plan, the switch to a government plan would cut that by $2,000 ($7,500 per year limited to $5,500 a year).

In 20 years, that would cost the employee $40,000 in lost savings, LIMRA says, excluding investment growth, fees, withdrawals, increases in salary, and other factors.

Then there are employer contributions—not allowed under a state-run plan—investment variety and education and investment diversity.

When it comes down to it, neither 401(k)s nor state-run plans were designed to replace defined benefit plans in saving for retirement.

Stepping down from an employer-provided 401(k) to a state-provided "starter" plan, rather than adding a state-run plan where there is no employer-provided plan, would be a move in the wrong direction.