Most people live paycheck to paycheck and don't make enough to save. AVERAGE salary in the US is only 36k.
http://66.102.7.104/search?q=cache:H...ient=firefox-a
That means the bi-weekly is around 1k or so give or take a few after taxes. That's not very much if you have bills to pay. Of course a lot of people make more but they are not the average.
Average person probably has 3-4 k at best I would guess.
A lot of my friends, (in their mid-late twenties) don't even have 3 or 4 k, and are more like living paycheck to paycheck or more like dollar to dollar.
When I had a 9-5 I was barely able to save ANYTHING after rent, bills, and then of course shopping.... I was only able to save once I started selling porn.