Lots of them do. However, most working age adults do not have stocks or portfolios. And dont believe that scammy 60 percent number that came from a Gallup poll that democraps like Brennan are citing, its bunko.
The 401 s are usually in some stocks. Mutual funds are a mix of stocks. A lot of people rely on the market for part of their retirement. The number was probably pulled out of his butt though.