Ted Benna, the retirement consultant widely credited with helping create the modern 401(k), now believes the retirement plan has fallen short for many lower-income workers.

Benna, now 84, believes many middle- and lower-income workers cannot afford to contribute to a 401(k), even when their employers offer one, in an interview with Bloomberg published on Tuesday.

"The 401(k) isn't working really well now for many middle- and lower-income employees," Benna told Bloomberg, adding that "many of them can't afford to have money taken out of their paycheck even if they have the opportunity to do so." Rather than relying on workers to set aside part of every paycheck, Benna wants employers to help them build savings through a new program called Radish.

What Is Radish?

More than two-thirds of private-sector workers have access to 401(k)-type retirement plans, but only about half of eligible workers participate, according to the U.S.