I have no doubt about the 42% number. I think many think about saving but often things happen which unless you are in that category its hard to understand.
Like if you have less than $5k in your 401k many companies send you a check automatically when you stop working there.. well if you just got layed off and got a check for $2500 from your company, you don't think hey I should roll this over into my IRA, you think OMG I can pay my bills another month until I find something else.
Generational issues play a big part, every time you have a few dollars, there is always a kid/grandkid that is on the edge, car won't start, furnace broke, etc.. its a "it takes a village" type situation and well the village is cumulatively always broke.
And then there is just the fact most people are like, well I'm poor now, how much poorer can I really get.. so why not get at least something for myself now. If you make $15/hr and you save 3%, you are talking $900 a year, that is not going to change their life even 30 years from now...but $900 now could mean a car that doesnt break down every day or an apartment you feel safer in or a family trip to some local water park. clothes from some place other than good will, etc.
And of course a huge group of people that have a very skewed sense of reality.. it always amazes me when every story starts, well I'm 50+, $60k on the credit cards (but hey who doesn't), have a house which I will owe payments on until I'm 80, but I've saved away all this money, like I have almost $20k in my 401k so I'm not doing that bad. They honestly think they are doing great.. like they own their own home, have money in their 401k, so obviously they are doing way better than most.