Sure, but given that the median income in the US is $51,939 (2013) I think it's safe to assume that most people (in the US) can gain a lot by following the simp

Sure, but given that the median income in the US is $51,939 (2013) I think it's safe to assume that most people (in the US) can gain a lot by following the simple tenant of spend less, save more. But even MMM has suggestions for people who make too little - I suspect most finance blogs do. MMM advocates getting into a profession where you can make at least the median income, because that's obviously the easiest way to increase your potential savings if you're low-income.