When you add together the costs of housing, transportation, food, medical care, etc., it is very unlikely that poker will allow you to earn enough to not need another source of income. As has been said, the amount of grinding you'd have to do to have enough money from poker is not what most people are able to do.
While I'd love to win millions in some big tournament score (wouldn't that be fun), poker is a hobby that can sometimes earn me money. I have won more money playing poker than I have ever spent, but we're talking a very small amount of money in total!