Contrary to popular belief, most people live check to check or damn close to it. This includes a significant portion of people who make 6 figures or close to it. Ask anyone who has experience in personal finance.
On a side note, more and more people leave money that would have gone into a savings account, into various investment accounts instead. This is part of the reason as well. People invest their money more than ever now which means less and less leave it sitting in savings accruing practically nothing.