You take FICA out, some federal/state taxes, you've got less than $2k a month. That doesn't stretch too far in some places.

Also, since you're lower working class, you're not going to be buying in bulk. You're not going to be avoiding late fees. You're not going to have economies of scale available to you on a $100k annual income.

So, the ability to save $5.5k is much different for someone earning $25k vs $100k. I'm not saying it's outright impossible, but it will have measurable impact on lifestyle for the lower income worker, whereas not so much for the higher income worker, since each marginal dollar you earn provides less and less utility. But the first $25k you earn really is your lifeline to meet basic necessities in life.