Recessions like 2008 are part of the normal ebb and flow of the markets, and we're likely heading into another one (though hopefully not quite so bad). 5-6 years earlier wouldn't have made a noticeable difference unless they were planning on retiring between 2008-2012ish, the markets have recovered after all.
Personally, if I see the stock market dip like that again I'm going to double down on my 401(k) contributions.