We need to consider education costs in the cost of living. In today’s world, a person cannot make enough money to survive without education and job training. (Job training includes learning business management, for those starting their own small business.) To get an education, most students need to take out student loans. These student loans need to include the cost of necessities such as food, clothes, shelter, and healthcare, because a person needs to survive comfortably to get educated properly. This leaves the student with debt. Thus, we have to consider this debt in the cost of living.
Normally, the cost of living refers to how much it costs for a person to afford the necessities of modern life–namely food, clothes, shelter and healthcare. If a person makes enough to afford those necessities, then we do not consider the person poor. If the person does not make enough to afford those necessities, then we do consider the person poor.
Since a person needs the education to make their income in the first place, we cannot reasonably consider a person non-poor if the person cannot afford to pay off their student loans, even if the person makes enough to pay for their current food, clothes, shelter, and healthcare.