I do not know how material poverty can be defined. I have an easier time defining poverty of spirit. Man can not live on bread alone, and material appurtenances are no measure of quality of life.
(I have mentioned before two "poor" people I have come to know well: a Maine Guide who lives with his family in an unelectrified log cabin built by his own hands and who home-schools, and a New Hampshire farmer who attends my church whose life is as spartan and spare as that of the Guide, but whose life is full of joy, accomplishment, friends, pride, and serenity - except when his equipment breaks.)
Few people get this as well as my fellow shrink Dr. Ted Dalrymple, a man who has seen it all both in the jails and government housing of England and around the world. Sympathy Deformed: Misguided compassion hurts the poor.
The examples from Africa are heartbreaking.
Given all that, I am grateful to be what I am, an American professional woman married to a Boston finance guy with money to spare. He still plays Rugby and hockey, and I never lacked for life spirit either. We lack neither the Holy sort nor the secular sort of spirit, I think, and Shame On You if you do not jump into the thick of life and grab it by the balls the ball. Our family motto is a Nike ad. I do not need much in material comforts, but I do like and desire other things, including a closer walk with Christ. There is something about having spare money that causes one to want less material stuff, at least for me.
As our Editor says, a new car is a used car after 24 hours. Thoreau would have said the same thing, but it was all hypothetical for him. He had a family business (always a good thing to have).